src/modules/m_repeat.cpp

   1 /*
   2  * InspIRCd -- Internet Relay Chat Daemon
   3  *
   4  *   Copyright (C) 2019 Robby <robby@chatbelgie.be>
   5  *   Copyright (C) 2018-2019 linuxdaemon <linuxdaemon.irc@gmail.com>
   6  *   Copyright (C) 2018 Matt Schatz <genius3000@g3k.solutions>
   7  *   Copyright (C) 2017-2019 Sadie Powell <sadie@witchery.services>
   8  *   Copyright (C) 2015 James Lu <GLolol@overdrivenetworks.com>
   9  *   Copyright (C) 2013-2015 Attila Molnar <attilamolnar@hush.com>
  10  *   Copyright (C) 2013 Daniel Vassdal <shutter@canternet.org>
  11  *
  12  * This file is part of InspIRCd.  InspIRCd is free software: you can
  13  * redistribute it and/or modify it under the terms of the GNU General Public
  14  * License as published by the Free Software Foundation, version 2.
  15  *
  16  * This program is distributed in the hope that it will be useful, but WITHOUT
  17  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  18  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  19  * details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  23  */
  24
  25
  26 #include "inspircd.h"
  27 #include "modules/exemption.h"
  28
  29 class ChannelSettings
  30 {
  31  public:
  32         enum RepeatAction
  33         {
  34                 ACT_KICK,
  35                 ACT_BLOCK,
  36                 ACT_BAN
  37         };
  38
  39         RepeatAction Action;
  40         unsigned int Backlog;
  41         unsigned int Lines;
  42         unsigned int Diff;
  43         unsigned long Seconds;
  44
  45         void serialize(std::string& out) const
  46         {
  47                 if (Action == ACT_BAN)
  48                         out.push_back('*');
  49                 else if (Action == ACT_BLOCK)
  50                         out.push_back('~');
  51
  52                 out.append(ConvToStr(Lines)).push_back(':');
  53                 out.append(ConvToStr(Seconds));
  54                 if (Diff)
  55                 {
  56                         out.push_back(':');
  57                         out.append(ConvToStr(Diff));
  58                         if (Backlog)
  59                         {
  60                                 out.push_back(':');
  61                                 out.append(ConvToStr(Backlog));
  62                         }
  63                 }
  64         }
  65 };
  66
  67 class RepeatMode : public ParamMode<RepeatMode, SimpleExtItem<ChannelSettings> >
  68 {
  69  private:
  70         struct RepeatItem
  71         {
  72                 time_t ts;
  73                 std::string line;
  74                 RepeatItem(time_t TS, const std::string& Line) : ts(TS), line(Line) { }
  75         };
  76
  77         typedef std::deque<RepeatItem> RepeatItemList;
  78
  79         struct MemberInfo
  80         {
  81                 RepeatItemList ItemList;
  82                 unsigned int Counter;
  83                 MemberInfo() : Counter(0) {}
  84         };
  85
  86         struct ModuleSettings
  87         {
  88                 unsigned int MaxLines;
  89                 unsigned int MaxSecs;
  90                 unsigned int MaxBacklog;
  91                 unsigned int MaxDiff;
  92                 unsigned int MaxMessageSize;
  93                 std::string KickMessage;
  94                 ModuleSettings() : MaxLines(0), MaxSecs(0), MaxBacklog(0), MaxDiff() { }
  95         };
  96
  97         std::vector<unsigned int> mx[2];
  98         ModuleSettings ms;
  99
 100         bool CompareLines(const std::string& message, const std::string& historyline, unsigned int trigger)
 101         {
 102                 if (message == historyline)
 103                         return true;
 104                 else if (trigger)
 105                         return (Levenshtein(message, historyline) <= trigger);
 106
 107                 return false;
 108         }
 109
 110         unsigned int Levenshtein(const std::string& s1, const std::string& s2)
 111         {
 112                 unsigned int l1 = s1.size();
 113                 unsigned int l2 = s2.size();
 114
 115                 for (unsigned int i = 0; i < l2; i++)
 116                         mx[0][i] = i;
 117                 for (unsigned int i = 0; i < l1; i++)
 118                 {
 119                         mx[1][0] = i + 1;
 120                         for (unsigned int j = 0; j < l2; j++)
 121                                 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));
 122
 123                         mx[0].swap(mx[1]);
 124                 }
 125                 return mx[0][l2];
 126         }
 127
 128  public:
 129         SimpleExtItem<MemberInfo> MemberInfoExt;
 130
 131         RepeatMode(Module* Creator)
 132                 : ParamMode<RepeatMode, SimpleExtItem<ChannelSettings> >(Creator, "repeat", 'E')
 133                 , MemberInfoExt("repeat_memb", ExtensionItem::EXT_MEMBERSHIP, Creator)
 134         {
 135                 syntax = "[~|*]<lines>:<sec>[:<difference>][:<backlog>]";
 136         }
 137
 138         void OnUnset(User* source, Channel* chan) CXX11_OVERRIDE
 139         {
 140                 // Unset the per-membership extension when the mode is removed
 141                 const Channel::MemberMap& users = chan->GetUsers();
 142                 for (Channel::MemberMap::const_iterator i = users.begin(); i != users.end(); ++i)
 143                         MemberInfoExt.unset(i->second);
 144         }
 145
 146         ModeAction OnSet(User* source, Channel* channel, std::string& parameter) CXX11_OVERRIDE
 147         {
 148                 ChannelSettings settings;
 149                 if (!ParseSettings(source, parameter, settings))
 150                 {
 151                         source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter));
 152                         return MODEACTION_DENY;
 153                 }
 154
 155                 if ((settings.Backlog > 0) && (settings.Lines > settings.Backlog))
 156                 {
 157                         source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter,
 158                                 "You can't set lines higher than backlog."));
 159                         return MODEACTION_DENY;
 160                 }
 161
 162                 LocalUser* localsource = IS_LOCAL(source);
 163                 if ((localsource) && (!ValidateSettings(localsource, channel, parameter, settings)))
 164                         return MODEACTION_DENY;
 165
 166                 ext.set(channel, settings);
 167
 168                 return MODEACTION_ALLOW;
 169         }
 170
 171         bool MatchLine(Membership* memb, ChannelSettings* rs, std::string message)
 172         {
 173                 // If the message is larger than whatever size it's set to,
 174                 // let's pretend it isn't. If the first 512 (def. setting) match, it's probably spam.
 175                 if (message.size() > ms.MaxMessageSize)
 176                         message.erase(ms.MaxMessageSize);
 177
 178                 MemberInfo* rp = MemberInfoExt.get(memb);
 179                 if (!rp)
 180                 {
 181                         rp = new MemberInfo;
 182                         MemberInfoExt.set(memb, rp);
 183                 }
 184
 185                 unsigned int matches = 0;
 186                 if (!rs->Backlog)
 187                         matches = rp->Counter;
 188
 189                 RepeatItemList& items = rp->ItemList;
 190                 const unsigned int trigger = (message.size() * rs->Diff / 100);
 191                 const time_t now = ServerInstance->Time();
 192
 193                 std::transform(message.begin(), message.end(), message.begin(), ::tolower);
 194
 195                 for (std::deque<RepeatItem>::iterator it = items.begin(); it != items.end(); ++it)
 196                 {
 197                         if (it->ts < now)
 198                         {
 199                                 items.erase(it, items.end());
 200                                 matches = 0;
 201                                 break;
 202                         }
 203
 204                         if (CompareLines(message, it->line, trigger))
 205                         {
 206                                 if (++matches >= rs->Lines)
 207                                 {
 208                                         if (rs->Action != ChannelSettings::ACT_BLOCK)
 209                                                 rp->Counter = 0;
 210                                         return true;
 211                                 }
 212                         }
 213                         else if ((ms.MaxBacklog == 0) || (rs->Backlog == 0))
 214                         {
 215                                 matches = 0;
 216                                 items.clear();
 217                                 break;
 218                         }
 219                 }
 220
 221                 unsigned int max_items = (rs->Backlog ? rs->Backlog : 1);
 222                 if (items.size() >= max_items)
 223                         items.pop_back();
 224
 225                 items.push_front(RepeatItem(now + rs->Seconds, message));
 226                 rp->Counter = matches;
 227                 return false;
 228         }
 229
 230         void Resize(size_t size)
 231         {
 232                 size_t newsize = size+1;
 233                 if (newsize <= mx[0].size())
 234                         return;
 235                 ms.MaxMessageSize = size;
 236                 mx[0].resize(newsize);
 237                 mx[1].resize(newsize);
 238         }
 239
 240         void ReadConfig()
 241         {
 242                 ConfigTag* conf = ServerInstance->Config->ConfValue("repeat");
 243                 ms.MaxLines = conf->getUInt("maxlines", 20);
 244                 ms.MaxBacklog = conf->getUInt("maxbacklog", 20);
 245                 ms.MaxSecs = conf->getDuration("maxtime", conf->getDuration("maxsecs", 0));
 246
 247                 ms.MaxDiff = conf->getUInt("maxdistance", 50);
 248                 if (ms.MaxDiff > 100)
 249                         ms.MaxDiff = 100;
 250
 251                 unsigned int newsize = conf->getUInt("size", 512);
 252                 if (newsize > ServerInstance->Config->Limits.MaxLine)
 253                         newsize = ServerInstance->Config->Limits.MaxLine;
 254                 Resize(newsize);
 255
 256                 ms.KickMessage = conf->getString("kickmessage", "Repeat flood");
 257         }
 258
 259         std::string GetModuleSettings() const
 260         {
 261                 return ConvToStr(ms.MaxLines) + ":" + ConvToStr(ms.MaxSecs) + ":" + ConvToStr(ms.MaxDiff) + ":" + ConvToStr(ms.MaxBacklog);
 262         }
 263
 264         std::string GetKickMessage() const
 265         {
 266                 return ms.KickMessage;
 267         }
 268
 269         void SerializeParam(Channel* chan, const ChannelSettings* chset, std::string& out)
 270         {
 271                 chset->serialize(out);
 272         }
 273
 274  private:
 275         bool ParseSettings(User* source, std::string& parameter, ChannelSettings& settings)
 276         {
 277                 irc::sepstream stream(parameter, ':');
 278                 std::string     item;
 279                 if (!stream.GetToken(item))
 280                         // Required parameter missing
 281                         return false;
 282
 283                 if ((item[0] == '*') || (item[0] == '~'))
 284                 {
 285                         settings.Action = ((item[0] == '*') ? ChannelSettings::ACT_BAN : ChannelSettings::ACT_BLOCK);
 286                         item.erase(item.begin());
 287                 }
 288                 else
 289                         settings.Action = ChannelSettings::ACT_KICK;
 290
 291                 if ((settings.Lines = ConvToNum<unsigned int>(item)) == 0)
 292                         return false;
 293
 294                 if ((!stream.GetToken(item)) || !InspIRCd::Duration(item, settings.Seconds) || (settings.Seconds == 0))
 295                         // Required parameter missing
 296                         return false;
 297
 298                 // The diff and backlog parameters are optional
 299                 settings.Diff = settings.Backlog = 0;
 300                 if (stream.GetToken(item))
 301                 {
 302                         // There is a diff parameter, see if it's valid (> 0)
 303                         if ((settings.Diff = ConvToNum<unsigned int>(item)) == 0)
 304                                 return false;
 305
 306                         if (stream.GetToken(item))
 307                         {
 308                                 // There is a backlog parameter, see if it's valid
 309                                 if ((settings.Backlog = ConvToNum<unsigned int>(item)) == 0)
 310                                         return false;
 311
 312                                 // If there are still tokens, then it's invalid because we allow only 4
 313                                 if (stream.GetToken(item))
 314                                         return false;
 315                         }
 316                 }
 317
 318                 return true;
 319         }
 320
 321         bool ValidateSettings(LocalUser* source, Channel* channel, const std::string& parameter, const ChannelSettings& settings)
 322         {
 323                 if (ms.MaxLines && settings.Lines > ms.MaxLines)
 324                 {
 325                         source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter, InspIRCd::Format(
 326                                 "The line number you specified is too big. Maximum allowed is %u.", ms.MaxLines)));
 327                         return false;
 328                 }
 329
 330                 if (ms.MaxSecs && settings.Seconds > ms.MaxSecs)
 331                 {
 332                         source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter, InspIRCd::Format(
 333                                 "The seconds you specified are too big. Maximum allowed is %u.", ms.MaxSecs)));
 334                         return false;
 335                 }
 336
 337                 if (settings.Diff && settings.Diff > ms.MaxDiff)
 338                 {
 339                         if (ms.MaxDiff == 0)
 340                                 source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter,
 341                                         "The server administrator has disabled matching on edit distance."));
 342                         else
 343                                 source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter, InspIRCd::Format(
 344                                         "The distance you specified is too big. Maximum allowed is %u.", ms.MaxDiff)));
 345                         return false;
 346                 }
 347
 348                 if (settings.Backlog && settings.Backlog > ms.MaxBacklog)
 349                 {
 350                         if (ms.MaxBacklog == 0)
 351                                 source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter,
 352                                         "The server administrator has disabled backlog matching."));
 353                         else
 354                                 source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter, InspIRCd::Format(
 355                                         "The backlog you specified is too big. Maximum allowed is %u.", ms.MaxBacklog)));
 356                         return false;
 357                 }
 358
 359                 return true;
 360         }
 361 };
 362
 363 class RepeatModule : public Module
 364 {
 365         CheckExemption::EventProvider exemptionprov;
 366         RepeatMode rm;
 367
 368  public:
 369         RepeatModule()
 370                 : exemptionprov(this)
 371                 , rm(this)
 372         {
 373         }
 374
 375         void ReadConfig(ConfigStatus& status) CXX11_OVERRIDE
 376         {
 377                 rm.ReadConfig();
 378         }
 379
 380         ModResult OnUserPreMessage(User* user, const MessageTarget& target, MessageDetails& details) CXX11_OVERRIDE
 381         {
 382                 if (target.type != MessageTarget::TYPE_CHANNEL || !IS_LOCAL(user))
 383                         return MOD_RES_PASSTHRU;
 384
 385                 Channel* chan = target.Get<Channel>();
 386                 ChannelSettings* settings = rm.ext.get(chan);
 387                 if (!settings)
 388                         return MOD_RES_PASSTHRU;
 389
 390                 Membership* memb = chan->GetUser(user);
 391                 if (!memb)
 392                         return MOD_RES_PASSTHRU;
 393
 394                 ModResult res = CheckExemption::Call(exemptionprov, user, chan, "repeat");
 395                 if (res == MOD_RES_ALLOW)
 396                         return MOD_RES_PASSTHRU;
 397
 398                 if (rm.MatchLine(memb, settings, details.text))
 399                 {
 400                         if (settings->Action == ChannelSettings::ACT_BLOCK)
 401                         {
 402                                 user->WriteNotice("*** This line is too similar to one of your last lines.");
 403                                 return MOD_RES_DENY;
 404                         }
 405
 406                         if (settings->Action == ChannelSettings::ACT_BAN)
 407                         {
 408                                 Modes::ChangeList changelist;
 409                                 changelist.push_add(ServerInstance->Modes->FindMode('b', MODETYPE_CHANNEL), "*!*@" + user->GetDisplayedHost());
 410                                 ServerInstance->Modes->Process(ServerInstance->FakeClient, chan, NULL, changelist);
 411                         }
 412
 413                         memb->chan->KickUser(ServerInstance->FakeClient, user, rm.GetKickMessage());
 414                         return MOD_RES_DENY;
 415                 }
 416                 return MOD_RES_PASSTHRU;
 417         }
 418
 419         void Prioritize() CXX11_OVERRIDE
 420         {
 421                 ServerInstance->Modules->SetPriority(this, I_OnUserPreMessage, PRIORITY_LAST);
 422         }
 423
 424         Version GetVersion() CXX11_OVERRIDE
 425         {
 426                 return Version("Adds channel mode E (repeat) which helps protect against spammers which spam the same message repeatedly.", VF_COMMON|VF_VENDOR, rm.GetModuleSettings());
 427         }
 428 };
 429
 430 MODULE_INIT(RepeatModule)