src/modules/m_nickflood.cpp

   1 /*
   2  * InspIRCd -- Internet Relay Chat Daemon
   3  *
   4  *   Copyright (C) 2009 Daniel De Graaf <danieldg@inspircd.org>
   5  *   Copyright (C) 2007, 2009 Robin Burchell <robin+git@viroteck.net>
   6  *
   7  * This file is part of InspIRCd.  InspIRCd is free software: you can
   8  * redistribute it and/or modify it under the terms of the GNU General Public
   9  * License as published by the Free Software Foundation, version 2.
  10  *
  11  * This program is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  13  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  14  * details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20
  21 #include "inspircd.h"
  22
  23 /* $ModDesc: Provides channel mode +F (nick flood protection) */
  24
  25 /** Holds settings and state associated with channel mode +F
  26  */
  27 class nickfloodsettings
  28 {
  29  public:
  30         int secs;
  31         int nicks;
  32         time_t reset;
  33         time_t unlocktime;
  34         int counter;
  35         bool locked;
  36
  37         nickfloodsettings(int b, int c) : secs(b), nicks(c)
  38         {
  39                 reset = ServerInstance->Time() + secs;
  40                 counter = 0;
  41                 locked = false;
  42         };
  43
  44         void addnick()
  45         {
  46                 counter++;
  47                 if (ServerInstance->Time() > reset)
  48                 {
  49                         counter = 0;
  50                         reset = ServerInstance->Time() + secs;
  51                 }
  52         }
  53
  54         bool shouldlock()
  55         {
  56                 /* XXX HACK: using counter + 1 here now to allow the counter to only be incremented
  57                  * on successful nick changes; this will be checked before the counter is
  58                  * incremented.
  59                  */
  60                 return (counter + 1 >= this->nicks);
  61         }
  62
  63         void clear()
  64         {
  65                 counter = 0;
  66         }
  67
  68         bool islocked()
  69         {
  70                 if (locked)
  71                 {
  72                         if (ServerInstance->Time() > unlocktime)
  73                         {
  74                                 locked = false;
  75                                 return false;
  76                         }
  77                         else
  78                         {
  79                                 return true;
  80                         }
  81                 }
  82                 return false;
  83         }
  84
  85         void lock()
  86         {
  87                 locked = true;
  88                 unlocktime = ServerInstance->Time() + 60;
  89         }
  90
  91 };
  92
  93 /** Handles channel mode +j
  94  */
  95 class NickFlood : public ModeHandler
  96 {
  97  public:
  98         SimpleExtItem<nickfloodsettings> ext;
  99         NickFlood(Module* Creator) : ModeHandler(Creator, "nickflood", 'F', PARAM_SETONLY, MODETYPE_CHANNEL),
 100                 ext("nickflood", Creator) { }
 101
 102         ModeAction OnModeChange(User* source, User* dest, Channel* channel, std::string &parameter, bool adding)
 103         {
 104                 nickfloodsettings *f = ext.get(channel);
 105                 if (adding)
 106                 {
 107                         char ndata[MAXBUF];
 108                         char* data = ndata;
 109                         strlcpy(ndata,parameter.c_str(),MAXBUF);
 110                         char* nicks = data;
 111                         char* secs = NULL;
 112                         while (*data)
 113                         {
 114                                 if (*data == ':')
 115                                 {
 116                                         *data = 0;
 117                                         data++;
 118                                         secs = data;
 119                                         break;
 120                                 }
 121                                 else data++;
 122                         }
 123                         if (secs)
 124                         {
 125                                 /* Set up the flood parameters for this channel */
 126                                 int nnicks = atoi(nicks);
 127                                 int nsecs = atoi(secs);
 128                                 if ((nnicks<1) || (nsecs<1))
 129                                 {
 130                                         source->WriteNumeric(608, "%s %s :Invalid flood parameter",source->nick.c_str(),channel->name.c_str());
 131                                         parameter.clear();
 132                                         return MODEACTION_DENY;
 133                                 }
 134                                 else
 135                                 {
 136                                         if (!f)
 137                                         {
 138                                                 parameter = ConvToStr(nnicks) + ":" +ConvToStr(nsecs);
 139                                                 f = new nickfloodsettings(nsecs, nnicks);
 140                                                 ext.set(channel, f);
 141                                                 channel->SetModeParam('F', parameter);
 142                                                 return MODEACTION_ALLOW;
 143                                         }
 144                                         else
 145                                         {
 146                                                 std::string cur_param = channel->GetModeParameter('F');
 147                                                 parameter = ConvToStr(nnicks) + ":" +ConvToStr(nsecs);
 148                                                 if (cur_param == parameter)
 149                                                 {
 150                                                         // mode params match
 151                                                         return MODEACTION_DENY;
 152                                                 }
 153                                                 else
 154                                                 {
 155                                                         // new mode param, replace old with new
 156                                                         if ((nsecs > 0) && (nnicks > 0))
 157                                                         {
 158                                                                 f = new nickfloodsettings(nsecs, nnicks);
 159                                                                 ext.set(channel, f);
 160                                                                 channel->SetModeParam('F', parameter);
 161                                                                 return MODEACTION_ALLOW;
 162                                                         }
 163                                                         else
 164                                                         {
 165                                                                 return MODEACTION_DENY;
 166                                                         }
 167                                                 }
 168                                         }
 169                                 }
 170                         }
 171                         else
 172                         {
 173                                 source->WriteNumeric(608, "%s %s :Invalid flood parameter",source->nick.c_str(),channel->name.c_str());
 174                                 return MODEACTION_DENY;
 175                         }
 176                 }
 177                 else
 178                 {
 179                         if (f)
 180                         {
 181                                 ext.unset(channel);
 182                                 channel->SetModeParam('F', "");
 183                                 return MODEACTION_ALLOW;
 184                         }
 185                 }
 186                 return MODEACTION_DENY;
 187         }
 188 };
 189
 190 class ModuleNickFlood : public Module
 191 {
 192         NickFlood nf;
 193
 194  public:
 195
 196         ModuleNickFlood()
 197                 : nf(this)
 198         {
 199                 if (!ServerInstance->Modes->AddMode(&nf))
 200                         throw ModuleException("Could not add new modes!");
 201                 ServerInstance->Extensions.Register(&nf.ext);
 202                 Implementation eventlist[] = { I_OnUserPreNick, I_OnUserPostNick };
 203                 ServerInstance->Modules->Attach(eventlist, this, 2);
 204         }
 205
 206         ModResult OnUserPreNick(User* user, const std::string &newnick)
 207         {
 208                 if (ServerInstance->NICKForced.get(user)) /* Allow forced nick changes */
 209                         return MOD_RES_PASSTHRU;
 210
 211                 for (UCListIter i = user->chans.begin(); i != user->chans.end(); i++)
 212                 {
 213                         Channel *channel = *i;
 214                         ModResult res;
 215
 216                         nickfloodsettings *f = nf.ext.get(channel);
 217                         if (f)
 218                         {
 219                                 res = ServerInstance->OnCheckExemption(user,channel,"nickflood");
 220                                 if (res == MOD_RES_ALLOW)
 221                                         continue;
 222
 223                                 if (f->islocked())
 224                                 {
 225                                         user->WriteNumeric(447, "%s :%s has been locked for nickchanges for 60 seconds because there have been more than %d nick changes in %d seconds", user->nick.c_str(), channel->name.c_str(), f->nicks, f->secs);
 226                                         return MOD_RES_DENY;
 227                                 }
 228
 229                                 if (f->shouldlock())
 230                                 {
 231                                         f->clear();
 232                                         f->lock();
 233                                         channel->WriteChannelWithServ((char*)ServerInstance->Config->ServerName.c_str(), "NOTICE %s :No nick changes are allowed for 60 seconds because there have been more than %d nick changes in %d seconds.", channel->name.c_str(), f->nicks, f->secs);
 234                                         return MOD_RES_DENY;
 235                                 }
 236                         }
 237                 }
 238
 239                 return MOD_RES_PASSTHRU;
 240         }
 241
 242         /*
 243          * XXX: HACK: We do the increment on the *POST* event here (instead of all together) because we have no way of knowing whether other modules would block a nickchange.
 244          */
 245         void OnUserPostNick(User* user, const std::string &oldnick)
 246         {
 247                 if (isdigit(user->nick[0])) /* allow switches to UID */
 248                         return;
 249
 250                 for (UCListIter i = user->chans.begin(); i != user->chans.end(); ++i)
 251                 {
 252                         Channel *channel = *i;
 253                         ModResult res;
 254
 255                         nickfloodsettings *f = nf.ext.get(channel);
 256                         if (f)
 257                         {
 258                                 res = ServerInstance->OnCheckExemption(user,channel,"nickflood");
 259                                 if (res == MOD_RES_ALLOW)
 260                                         return;
 261
 262                                 /* moved this here to avoid incrementing the counter for nick
 263                                  * changes that are denied for some other reason (bans, +N, etc.)
 264                                  * per bug #874.
 265                                  */
 266                                 f->addnick();
 267                         }
 268                 }
 269                 return;
 270         }
 271
 272         ~ModuleNickFlood()
 273         {
 274         }
 275
 276         Version GetVersion()
 277         {
 278                 return Version("Channel mode F - nick flood protection", VF_VENDOR);
 279         }
 280 };
 281
 282 MODULE_INIT(ModuleNickFlood)