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 long 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) CXX11_OVERRIDE
 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) CXX11_OVERRIDE
 139         {
 140                 ChannelSettings settings;
 141                 if (!ParseSettings(source, parameter, settings))
 142                 {
 143                         source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter,
 144                                 "Invalid repeat syntax. Syntax is: [~|*]<lines>:<sec>[:<difference>][:<backlog>]"));
 145                         return MODEACTION_DENY;
 146                 }
 147
 148                 if ((settings.Backlog > 0) && (settings.Lines > settings.Backlog))
 149                 {
 150                         source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter,
 151                                 "Invalid repeat syntax. You can't set lines higher than backlog."));
 152                         return MODEACTION_DENY;
 153                 }
 154
 155                 LocalUser* localsource = IS_LOCAL(source);
 156                 if ((localsource) && (!ValidateSettings(localsource, channel, parameter, settings)))
 157                         return MODEACTION_DENY;
 158
 159                 ext.set(channel, settings);
 160
 161                 return MODEACTION_ALLOW;
 162         }
 163
 164         bool MatchLine(Membership* memb, ChannelSettings* rs, std::string message)
 165         {
 166                 // If the message is larger than whatever size it's set to,
 167                 // let's pretend it isn't. If the first 512 (def. setting) match, it's probably spam.
 168                 if (message.size() > ms.MaxMessageSize)
 169                         message.erase(ms.MaxMessageSize);
 170
 171                 MemberInfo* rp = MemberInfoExt.get(memb);
 172                 if (!rp)
 173                 {
 174                         rp = new MemberInfo;
 175                         MemberInfoExt.set(memb, rp);
 176                 }
 177
 178                 unsigned int matches = 0;
 179                 if (!rs->Backlog)
 180                         matches = rp->Counter;
 181
 182                 RepeatItemList& items = rp->ItemList;
 183                 const unsigned int trigger = (message.size() * rs->Diff / 100);
 184                 const time_t now = ServerInstance->Time();
 185
 186                 std::transform(message.begin(), message.end(), message.begin(), ::tolower);
 187
 188                 for (std::deque<RepeatItem>::iterator it = items.begin(); it != items.end(); ++it)
 189                 {
 190                         if (it->ts < now)
 191                         {
 192                                 items.erase(it, items.end());
 193                                 matches = 0;
 194                                 break;
 195                         }
 196
 197                         if (CompareLines(message, it->line, trigger))
 198                         {
 199                                 if (++matches >= rs->Lines)
 200                                 {
 201                                         if (rs->Action != ChannelSettings::ACT_BLOCK)
 202                                                 rp->Counter = 0;
 203                                         return true;
 204                                 }
 205                         }
 206                         else if ((ms.MaxBacklog == 0) || (rs->Backlog == 0))
 207                         {
 208                                 matches = 0;
 209                                 items.clear();
 210                                 break;
 211                         }
 212                 }
 213
 214                 unsigned int max_items = (rs->Backlog ? rs->Backlog : 1);
 215                 if (items.size() >= max_items)
 216                         items.pop_back();
 217
 218                 items.push_front(RepeatItem(now + rs->Seconds, message));
 219                 rp->Counter = matches;
 220                 return false;
 221         }
 222
 223         void Resize(size_t size)
 224         {
 225                 size_t newsize = size+1;
 226                 if (newsize <= mx[0].size())
 227                         return;
 228                 ms.MaxMessageSize = size;
 229                 mx[0].resize(newsize);
 230                 mx[1].resize(newsize);
 231         }
 232
 233         void ReadConfig()
 234         {
 235                 ConfigTag* conf = ServerInstance->Config->ConfValue("repeat");
 236                 ms.MaxLines = conf->getUInt("maxlines", 20);
 237                 ms.MaxBacklog = conf->getUInt("maxbacklog", 20);
 238                 ms.MaxSecs = conf->getDuration("maxtime", conf->getDuration("maxsecs", 0));
 239
 240                 ms.MaxDiff = conf->getUInt("maxdistance", 50);
 241                 if (ms.MaxDiff > 100)
 242                         ms.MaxDiff = 100;
 243
 244                 unsigned int newsize = conf->getUInt("size", 512);
 245                 if (newsize > ServerInstance->Config->Limits.MaxLine)
 246                         newsize = ServerInstance->Config->Limits.MaxLine;
 247                 Resize(newsize);
 248         }
 249
 250         std::string GetModuleSettings() const
 251         {
 252                 return ConvToStr(ms.MaxLines) + ":" + ConvToStr(ms.MaxSecs) + ":" + ConvToStr(ms.MaxDiff) + ":" + ConvToStr(ms.MaxBacklog);
 253         }
 254
 255         void SerializeParam(Channel* chan, const ChannelSettings* chset, std::string& out)
 256         {
 257                 chset->serialize(out);
 258         }
 259
 260  private:
 261         bool ParseSettings(User* source, std::string& parameter, ChannelSettings& settings)
 262         {
 263                 irc::sepstream stream(parameter, ':');
 264                 std::string     item;
 265                 if (!stream.GetToken(item))
 266                         // Required parameter missing
 267                         return false;
 268
 269                 if ((item[0] == '*') || (item[0] == '~'))
 270                 {
 271                         settings.Action = ((item[0] == '*') ? ChannelSettings::ACT_BAN : ChannelSettings::ACT_BLOCK);
 272                         item.erase(item.begin());
 273                 }
 274                 else
 275                         settings.Action = ChannelSettings::ACT_KICK;
 276
 277                 if ((settings.Lines = ConvToNum<unsigned int>(item)) == 0)
 278                         return false;
 279
 280                 if ((!stream.GetToken(item)) || !InspIRCd::Duration(item, settings.Seconds) || (settings.Seconds == 0))
 281                         // Required parameter missing
 282                         return false;
 283
 284                 // The diff and backlog parameters are optional
 285                 settings.Diff = settings.Backlog = 0;
 286                 if (stream.GetToken(item))
 287                 {
 288                         // There is a diff parameter, see if it's valid (> 0)
 289                         if ((settings.Diff = ConvToNum<unsigned int>(item)) == 0)
 290                                 return false;
 291
 292                         if (stream.GetToken(item))
 293                         {
 294                                 // There is a backlog parameter, see if it's valid
 295                                 if ((settings.Backlog = ConvToNum<unsigned int>(item)) == 0)
 296                                         return false;
 297
 298                                 // If there are still tokens, then it's invalid because we allow only 4
 299                                 if (stream.GetToken(item))
 300                                         return false;
 301                         }
 302                 }
 303
 304                 return true;
 305         }
 306
 307         bool ValidateSettings(LocalUser* source, Channel* channel, const std::string& parameter, const ChannelSettings& settings)
 308         {
 309                 if (ms.MaxLines && settings.Lines > ms.MaxLines)
 310                 {
 311                         source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter, InspIRCd::Format(
 312                                 "Invalid repeat parameter. The line number you specified is too great. Maximum allowed is %u.", ms.MaxLines)));
 313                         return false;
 314                 }
 315
 316                 if (ms.MaxSecs && settings.Seconds > ms.MaxSecs)
 317                 {
 318                         source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter, InspIRCd::Format(
 319                                 "Invalid repeat parameter. The seconds you specified are too great. Maximum allowed is %u.", ms.MaxSecs)));
 320                         return false;
 321                 }
 322
 323                 if (settings.Diff && settings.Diff > ms.MaxDiff)
 324                 {
 325                         if (ms.MaxDiff == 0)
 326                                 source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter,
 327                                         "Invalid repeat parameter. The server administrator has disabled matching on edit distance."));
 328                         else
 329                                 source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter, InspIRCd::Format(
 330                                         "Invalid repeat parameter. The distance you specified is too great. Maximum allowed is %u.", ms.MaxDiff)));
 331                         return false;
 332                 }
 333
 334                 if (settings.Backlog && settings.Backlog > ms.MaxBacklog)
 335                 {
 336                         if (ms.MaxBacklog == 0)
 337                                 source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter,
 338                                         "Invalid repeat parameter. The server administrator has disabled backlog matching."));
 339                         else
 340                                 source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter, InspIRCd::Format(
 341                                         "Invalid repeat paramter. The backlog you specified is too great. Maximum allowed is %u.", ms.MaxBacklog)));
 342                         return false;
 343                 }
 344
 345                 return true;
 346         }
 347 };
 348
 349 class RepeatModule : public Module
 350 {
 351         CheckExemption::EventProvider exemptionprov;
 352         RepeatMode rm;
 353
 354  public:
 355         RepeatModule()
 356                 : exemptionprov(this)
 357                 , rm(this)
 358         {
 359         }
 360
 361         void ReadConfig(ConfigStatus& status) CXX11_OVERRIDE
 362         {
 363                 rm.ReadConfig();
 364         }
 365
 366         ModResult OnUserPreMessage(User* user, const MessageTarget& target, MessageDetails& details) CXX11_OVERRIDE
 367         {
 368                 if (target.type != MessageTarget::TYPE_CHANNEL || !IS_LOCAL(user))
 369                         return MOD_RES_PASSTHRU;
 370
 371                 Channel* chan = target.Get<Channel>();
 372                 ChannelSettings* settings = rm.ext.get(chan);
 373                 if (!settings)
 374                         return MOD_RES_PASSTHRU;
 375
 376                 Membership* memb = chan->GetUser(user);
 377                 if (!memb)
 378                         return MOD_RES_PASSTHRU;
 379
 380                 ModResult res = CheckExemption::Call(exemptionprov, user, chan, "repeat");
 381                 if (res == MOD_RES_ALLOW)
 382                         return MOD_RES_PASSTHRU;
 383
 384                 if (rm.MatchLine(memb, settings, details.text))
 385                 {
 386                         if (settings->Action == ChannelSettings::ACT_BLOCK)
 387                         {
 388                                 user->WriteNotice("*** This line is too similar to one of your last lines.");
 389                                 return MOD_RES_DENY;
 390                         }
 391
 392                         if (settings->Action == ChannelSettings::ACT_BAN)
 393                         {
 394                                 Modes::ChangeList changelist;
 395                                 changelist.push_add(ServerInstance->Modes->FindMode('b', MODETYPE_CHANNEL), "*!*@" + user->GetDisplayedHost());
 396                                 ServerInstance->Modes->Process(ServerInstance->FakeClient, chan, NULL, changelist);
 397                         }
 398
 399                         memb->chan->KickUser(ServerInstance->FakeClient, user, "Repeat flood");
 400                         return MOD_RES_DENY;
 401                 }
 402                 return MOD_RES_PASSTHRU;
 403         }
 404
 405         void Prioritize() CXX11_OVERRIDE
 406         {
 407                 ServerInstance->Modules->SetPriority(this, I_OnUserPreMessage, PRIORITY_LAST);
 408         }
 409
 410         Version GetVersion() CXX11_OVERRIDE
 411         {
 412                 return Version("Provides channel mode +E, blocking of similar messages", VF_COMMON|VF_VENDOR, rm.GetModuleSettings());
 413         }
 414 };
 415
 416 MODULE_INIT(RepeatModule)