src/modules/m_repeat.cpp

   1 /*
   2  * InspIRCd -- Internet Relay Chat Daemon
   3  *
   4  *   Copyright (C) 2013 Daniel Vassdal <shutter@canternet.org>
   5  *
   6  * This file is part of InspIRCd.  InspIRCd is free software: you can
   7  * redistribute it and/or modify it under the terms of the GNU General Public
   8  * License as published by the Free Software Foundation, version 2.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  12  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  13  * details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19
  20 #include "inspircd.h"
  21 #include "modules/exemption.h"
  22
  23 class ChannelSettings
  24 {
  25  public:
  26         enum RepeatAction
  27         {
  28                 ACT_KICK,
  29                 ACT_BLOCK,
  30                 ACT_BAN
  31         };
  32
  33         RepeatAction Action;
  34         unsigned int Backlog;
  35         unsigned int Lines;
  36         unsigned int Diff;
  37         unsigned int Seconds;
  38
  39         void serialize(std::string& out) const
  40         {
  41                 if (Action == ACT_BAN)
  42                         out.push_back('*');
  43                 else if (Action == ACT_BLOCK)
  44                         out.push_back('~');
  45
  46                 out.append(ConvToStr(Lines)).push_back(':');
  47                 out.append(ConvToStr(Seconds));
  48                 if (Diff)
  49                 {
  50                         out.push_back(':');
  51                         out.append(ConvToStr(Diff));
  52                         if (Backlog)
  53                         {
  54                                 out.push_back(':');
  55                                 out.append(ConvToStr(Backlog));
  56                         }
  57                 }
  58         }
  59 };
  60
  61 class RepeatMode : public ParamMode<RepeatMode, SimpleExtItem<ChannelSettings> >
  62 {
  63  private:
  64         struct RepeatItem
  65         {
  66                 time_t ts;
  67                 std::string line;
  68                 RepeatItem(time_t TS, const std::string& Line) : ts(TS), line(Line) { }
  69         };
  70
  71         typedef std::deque<RepeatItem> RepeatItemList;
  72
  73         struct MemberInfo
  74         {
  75                 RepeatItemList ItemList;
  76                 unsigned int Counter;
  77                 MemberInfo() : Counter(0) {}
  78         };
  79
  80         struct ModuleSettings
  81         {
  82                 unsigned int MaxLines;
  83                 unsigned int MaxSecs;
  84                 unsigned int MaxBacklog;
  85                 unsigned int MaxDiff;
  86                 unsigned int MaxMessageSize;
  87                 ModuleSettings() : MaxLines(0), MaxSecs(0), MaxBacklog(0), MaxDiff() { }
  88         };
  89
  90         std::vector<unsigned int> mx[2];
  91         ModuleSettings ms;
  92
  93         bool CompareLines(const std::string& message, const std::string& historyline, unsigned int trigger)
  94         {
  95                 if (message == historyline)
  96                         return true;
  97                 else if (trigger)
  98                         return (Levenshtein(message, historyline) <= trigger);
  99
 100                 return false;
 101         }
 102
 103         unsigned int Levenshtein(const std::string& s1, const std::string& s2)
 104         {
 105                 unsigned int l1 = s1.size();
 106                 unsigned int l2 = s2.size();
 107
 108                 for (unsigned int i = 0; i < l2; i++)
 109                         mx[0][i] = i;
 110                 for (unsigned int i = 0; i < l1; i++)
 111                 {
 112                         mx[1][0] = i + 1;
 113                         for (unsigned int j = 0; j < l2; j++)
 114                                 mx[1][j + 1] = std::min(std::min(mx[1][j] + 1, mx[0][j + 1] + 1), mx[0][j] + ((s1[i] == s2[j]) ? 0 : 1));
 115
 116                         mx[0].swap(mx[1]);
 117                 }
 118                 return mx[0][l2];
 119         }
 120
 121  public:
 122         SimpleExtItem<MemberInfo> MemberInfoExt;
 123
 124         RepeatMode(Module* Creator)
 125                 : ParamMode<RepeatMode, SimpleExtItem<ChannelSettings> >(Creator, "repeat", 'E')
 126                 , MemberInfoExt("repeat_memb", ExtensionItem::EXT_MEMBERSHIP, Creator)
 127         {
 128         }
 129
 130         void OnUnset(User* source, Channel* chan)
 131         {
 132                 // Unset the per-membership extension when the mode is removed
 133                 const Channel::MemberMap& users = chan->GetUsers();
 134                 for (Channel::MemberMap::const_iterator i = users.begin(); i != users.end(); ++i)
 135                         MemberInfoExt.unset(i->second);
 136         }
 137
 138         ModeAction OnSet(User* source, Channel* channel, std::string& parameter)
 139         {
 140                 ChannelSettings settings;
 141                 if (!ParseSettings(source, parameter, settings))
 142                 {
 143                         source->WriteNotice("*** Invalid syntax. Syntax is {[~*]}[lines]:[time]{:[difference]}{:[backlog]}");
 144                         return MODEACTION_DENY;
 145                 }
 146
 147                 if ((settings.Backlog > 0) && (settings.Lines > settings.Backlog))
 148                 {
 149                         source->WriteNotice("*** You can't set needed lines higher than backlog");
 150                         return MODEACTION_DENY;
 151                 }
 152
 153                 LocalUser* localsource = IS_LOCAL(source);
 154                 if ((localsource) && (!ValidateSettings(localsource, settings)))
 155                         return MODEACTION_DENY;
 156
 157                 ext.set(channel, settings);
 158
 159                 return MODEACTION_ALLOW;
 160         }
 161
 162         bool MatchLine(Membership* memb, ChannelSettings* rs, std::string message)
 163         {
 164                 // If the message is larger than whatever size it's set to,
 165                 // let's pretend it isn't. If the first 512 (def. setting) match, it's probably spam.
 166                 if (message.size() > ms.MaxMessageSize)
 167                         message.erase(ms.MaxMessageSize);
 168
 169                 MemberInfo* rp = MemberInfoExt.get(memb);
 170                 if (!rp)
 171                 {
 172                         rp = new MemberInfo;
 173                         MemberInfoExt.set(memb, rp);
 174                 }
 175
 176                 unsigned int matches = 0;
 177                 if (!rs->Backlog)
 178                         matches = rp->Counter;
 179
 180                 RepeatItemList& items = rp->ItemList;
 181                 const unsigned int trigger = (message.size() * rs->Diff / 100);
 182                 const time_t now = ServerInstance->Time();
 183
 184                 std::transform(message.begin(), message.end(), message.begin(), ::tolower);
 185
 186                 for (std::deque<RepeatItem>::iterator it = items.begin(); it != items.end(); ++it)
 187                 {
 188                         if (it->ts < now)
 189                         {
 190                                 items.erase(it, items.end());
 191                                 matches = 0;
 192                                 break;
 193                         }
 194
 195                         if (CompareLines(message, it->line, trigger))
 196                         {
 197                                 if (++matches >= rs->Lines)
 198                                 {
 199                                         if (rs->Action != ChannelSettings::ACT_BLOCK)
 200                                                 rp->Counter = 0;
 201                                         return true;
 202                                 }
 203                         }
 204                         else if ((ms.MaxBacklog == 0) || (rs->Backlog == 0))
 205                         {
 206                                 matches = 0;
 207                                 items.clear();
 208                                 break;
 209                         }
 210                 }
 211
 212                 unsigned int max_items = (rs->Backlog ? rs->Backlog : 1);
 213                 if (items.size() >= max_items)
 214                         items.pop_back();
 215
 216                 items.push_front(RepeatItem(now + rs->Seconds, message));
 217                 rp->Counter = matches;
 218                 return false;
 219         }
 220
 221         void Resize(size_t size)
 222         {
 223                 size_t newsize = size+1;
 224                 if (newsize <= mx[0].size())
 225                         return;
 226                 ms.MaxMessageSize = size;
 227                 mx[0].resize(newsize);
 228                 mx[1].resize(newsize);
 229         }
 230
 231         void ReadConfig()
 232         {
 233                 ConfigTag* conf = ServerInstance->Config->ConfValue("repeat");
 234                 ms.MaxLines = conf->getInt("maxlines", 20);
 235                 ms.MaxBacklog = conf->getInt("maxbacklog", 20);
 236                 ms.MaxSecs = conf->getDuration("maxtime", conf->getInt("maxsecs", 0));
 237
 238                 ms.MaxDiff = conf->getInt("maxdistance", 50);
 239                 if (ms.MaxDiff > 100)
 240                         ms.MaxDiff = 100;
 241
 242                 unsigned int newsize = conf->getInt("size", 512);
 243                 if (newsize > ServerInstance->Config->Limits.MaxLine)
 244                         newsize = ServerInstance->Config->Limits.MaxLine;
 245                 Resize(newsize);
 246         }
 247
 248         std::string GetModuleSettings() const
 249         {
 250                 return ConvToStr(ms.MaxLines) + ":" + ConvToStr(ms.MaxSecs) + ":" + ConvToStr(ms.MaxDiff) + ":" + ConvToStr(ms.MaxBacklog);
 251         }
 252
 253         void SerializeParam(Channel* chan, const ChannelSettings* chset, std::string& out)
 254         {
 255                 chset->serialize(out);
 256         }
 257
 258  private:
 259         bool ParseSettings(User* source, std::string& parameter, ChannelSettings& settings)
 260         {
 261                 irc::sepstream stream(parameter, ':');
 262                 std::string     item;
 263                 if (!stream.GetToken(item))
 264                         // Required parameter missing
 265                         return false;
 266
 267                 if ((item[0] == '*') || (item[0] == '~'))
 268                 {
 269                         settings.Action = ((item[0] == '*') ? ChannelSettings::ACT_BAN : ChannelSettings::ACT_BLOCK);
 270                         item.erase(item.begin());
 271                 }
 272                 else
 273                         settings.Action = ChannelSettings::ACT_KICK;
 274
 275                 if ((settings.Lines = ConvToInt(item)) == 0)
 276                         return false;
 277
 278                 if ((!stream.GetToken(item)) || ((settings.Seconds = InspIRCd::Duration(item)) == 0))
 279                         // Required parameter missing
 280                         return false;
 281
 282                 // The diff and backlog parameters are optional
 283                 settings.Diff = settings.Backlog = 0;
 284                 if (stream.GetToken(item))
 285                 {
 286                         // There is a diff parameter, see if it's valid (> 0)
 287                         if ((settings.Diff = ConvToInt(item)) == 0)
 288                                 return false;
 289
 290                         if (stream.GetToken(item))
 291                         {
 292                                 // There is a backlog parameter, see if it's valid
 293                                 if ((settings.Backlog = ConvToInt(item)) == 0)
 294                                         return false;
 295
 296                                 // If there are still tokens, then it's invalid because we allow only 4
 297                                 if (stream.GetToken(item))
 298                                         return false;
 299                         }
 300                 }
 301
 302                 return true;
 303         }
 304
 305         bool ValidateSettings(LocalUser* source, const ChannelSettings& settings)
 306         {
 307                 if (settings.Backlog && !ms.MaxBacklog)
 308                 {
 309                         source->WriteNotice("*** The server administrator has disabled backlog matching");
 310                         return false;
 311                 }
 312
 313                 if (settings.Diff)
 314                 {
 315                         if (settings.Diff > ms.MaxDiff)
 316                         {
 317                                 if (ms.MaxDiff == 0)
 318                                         source->WriteNotice("*** The server administrator has disabled matching on edit distance");
 319                                 else
 320                                         source->WriteNotice("*** The distance you specified is too great. Maximum allowed is " + ConvToStr(ms.MaxDiff));
 321                                 return false;
 322                         }
 323
 324                         if (ms.MaxLines && settings.Lines > ms.MaxLines)
 325                         {
 326                                 source->WriteNotice("*** The line number you specified is too great. Maximum allowed is " + ConvToStr(ms.MaxLines));
 327                                 return false;
 328                         }
 329
 330                         if (ms.MaxSecs && settings.Seconds > ms.MaxSecs)
 331                         {
 332                                 source->WriteNotice("*** The seconds you specified is too great. Maximum allowed is " + ConvToStr(ms.MaxSecs));
 333                                 return false;
 334                         }
 335                 }
 336
 337                 return true;
 338         }
 339 };
 340
 341 class RepeatModule : public Module
 342 {
 343         CheckExemption::EventProvider exemptionprov;
 344         RepeatMode rm;
 345
 346  public:
 347         RepeatModule()
 348                 : exemptionprov(this)
 349                 , rm(this)
 350         {
 351         }
 352
 353         void ReadConfig(ConfigStatus& status) CXX11_OVERRIDE
 354         {
 355                 rm.ReadConfig();
 356         }
 357
 358         ModResult OnUserPreMessage(User* user, void* dest, int target_type, std::string& text, char status, CUList& exempt_list, MessageType msgtype) CXX11_OVERRIDE
 359         {
 360                 if (target_type != TYPE_CHANNEL || !IS_LOCAL(user))
 361                         return MOD_RES_PASSTHRU;
 362
 363                 Channel* chan = reinterpret_cast<Channel*>(dest);
 364                 ChannelSettings* settings = rm.ext.get(chan);
 365                 if (!settings)
 366                         return MOD_RES_PASSTHRU;
 367
 368                 Membership* memb = chan->GetUser(user);
 369                 if (!memb)
 370                         return MOD_RES_PASSTHRU;
 371
 372                 ModResult res = CheckExemption::Call(exemptionprov, user, chan, "repeat");
 373                 if (res == MOD_RES_ALLOW)
 374                         return MOD_RES_PASSTHRU;
 375
 376                 if (rm.MatchLine(memb, settings, text))
 377                 {
 378                         if (settings->Action == ChannelSettings::ACT_BLOCK)
 379                         {
 380                                 user->WriteNotice("*** This line is too similar to one of your last lines.");
 381                                 return MOD_RES_DENY;
 382                         }
 383
 384                         if (settings->Action == ChannelSettings::ACT_BAN)
 385                         {
 386                                 Modes::ChangeList changelist;
 387                                 changelist.push_add(ServerInstance->Modes->FindMode('b', MODETYPE_CHANNEL), "*!*@" + user->dhost);
 388                                 ServerInstance->Modes->Process(ServerInstance->FakeClient, chan, NULL, changelist);
 389                         }
 390
 391                         memb->chan->KickUser(ServerInstance->FakeClient, user, "Repeat flood");
 392                         return MOD_RES_DENY;
 393                 }
 394                 return MOD_RES_PASSTHRU;
 395         }
 396
 397         void Prioritize() CXX11_OVERRIDE
 398         {
 399                 ServerInstance->Modules->SetPriority(this, I_OnUserPreMessage, PRIORITY_LAST);
 400         }
 401
 402         Version GetVersion() CXX11_OVERRIDE
 403         {
 404                 return Version("Provides the +E channel mode - for blocking of similar messages", VF_COMMON|VF_VENDOR, rm.GetModuleSettings());
 405         }
 406 };
 407
 408 MODULE_INIT(RepeatModule)