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         unsigned int secs;
  31         unsigned int nicks;
  32         time_t reset;
  33         time_t unlocktime;
  34         unsigned int counter;
  35
  36         nickfloodsettings(unsigned int b, unsigned int c)
  37                 : secs(b), nicks(c), unlocktime(0), counter(0)
  38         {
  39                 reset = ServerInstance->Time() + secs;
  40         }
  41
  42         void addnick()
  43         {
  44                 if (ServerInstance->Time() > reset)
  45                 {
  46                         counter = 1;
  47                         reset = ServerInstance->Time() + secs;
  48                 }
  49                 else
  50                         counter++;
  51         }
  52
  53         bool shouldlock()
  54         {
  55                 /* XXX HACK: using counter + 1 here now to allow the counter to only be incremented
  56                  * on successful nick changes; this will be checked before the counter is
  57                  * incremented.
  58                  */
  59                 return ((ServerInstance->Time() <= reset) && (counter == this->nicks));
  60         }
  61
  62         void clear()
  63         {
  64                 counter = 0;
  65         }
  66
  67         bool islocked()
  68         {
  69                 if (ServerInstance->Time() > unlocktime)
  70                         unlocktime = 0;
  71
  72                 return (unlocktime != 0);
  73         }
  74
  75         void lock()
  76         {
  77                 unlocktime = ServerInstance->Time() + 60;
  78         }
  79 };
  80
  81 /** Handles channel mode +F
  82  */
  83 class NickFlood : public ModeHandler
  84 {
  85  public:
  86         SimpleExtItem<nickfloodsettings> ext;
  87         NickFlood(Module* Creator) : ModeHandler(Creator, "nickflood", 'F', PARAM_SETONLY, MODETYPE_CHANNEL),
  88                 ext("nickflood", Creator) { }
  89
  90         ModeAction OnModeChange(User* source, User* dest, Channel* channel, std::string &parameter, bool adding)
  91         {
  92                 if (adding)
  93                 {
  94                         std::string::size_type colon = parameter.find(':');
  95                         if ((colon == std::string::npos) || (parameter.find('-') != std::string::npos))
  96                         {
  97                                 source->WriteNumeric(608, "%s %s :Invalid flood parameter",source->nick.c_str(),channel->name.c_str());
  98                                 return MODEACTION_DENY;
  99                         }
 100
 101                         /* Set up the flood parameters for this channel */
 102                         unsigned int nnicks = ConvToInt(parameter.substr(0, colon));
 103                         unsigned int nsecs = ConvToInt(parameter.substr(colon+1));
 104
 105                         if ((nnicks<1) || (nsecs<1))
 106                         {
 107                                 source->WriteNumeric(608, "%s %s :Invalid flood parameter",source->nick.c_str(),channel->name.c_str());
 108                                 return MODEACTION_DENY;
 109                         }
 110
 111                         nickfloodsettings* f = ext.get(channel);
 112                         if ((f) && (nnicks == f->nicks) && (nsecs == f->secs))
 113                                 // mode params match
 114                                 return MODEACTION_DENY;
 115
 116                         ext.set(channel, new nickfloodsettings(nsecs, nnicks));
 117                         parameter = ConvToStr(nnicks) + ":" + ConvToStr(nsecs);
 118                         channel->SetModeParam('F', parameter);
 119                         return MODEACTION_ALLOW;
 120                 }
 121                 else
 122                 {
 123                         if (!channel->IsModeSet('F'))
 124                                 return MODEACTION_DENY;
 125
 126                         ext.unset(channel);
 127                         channel->SetModeParam('F', "");
 128                         return MODEACTION_ALLOW;
 129                 }
 130         }
 131 };
 132
 133 class ModuleNickFlood : public Module
 134 {
 135         NickFlood nf;
 136
 137  public:
 138
 139         ModuleNickFlood()
 140                 : nf(this)
 141         {
 142         }
 143
 144         void init()
 145         {
 146                 ServerInstance->Modules->AddService(nf);
 147                 ServerInstance->Modules->AddService(nf.ext);
 148                 Implementation eventlist[] = { I_OnUserPreNick, I_OnUserPostNick };
 149                 ServerInstance->Modules->Attach(eventlist, this, sizeof(eventlist)/sizeof(Implementation));
 150         }
 151
 152         ModResult OnUserPreNick(User* user, const std::string &newnick)
 153         {
 154                 if (ServerInstance->NICKForced.get(user)) /* Allow forced nick changes */
 155                         return MOD_RES_PASSTHRU;
 156
 157                 for (UCListIter i = user->chans.begin(); i != user->chans.end(); i++)
 158                 {
 159                         Channel *channel = *i;
 160                         ModResult res;
 161
 162                         nickfloodsettings *f = nf.ext.get(channel);
 163                         if (f)
 164                         {
 165                                 res = ServerInstance->OnCheckExemption(user,channel,"nickflood");
 166                                 if (res == MOD_RES_ALLOW)
 167                                         continue;
 168
 169                                 if (f->islocked())
 170                                 {
 171                                         user->WriteNumeric(447, "%s :%s has been locked for nickchanges for 60 seconds because there have been more than %u nick changes in %u seconds", user->nick.c_str(), channel->name.c_str(), f->nicks, f->secs);
 172                                         return MOD_RES_DENY;
 173                                 }
 174
 175                                 if (f->shouldlock())
 176                                 {
 177                                         f->clear();
 178                                         f->lock();
 179                                         channel->WriteChannelWithServ((char*)ServerInstance->Config->ServerName.c_str(), "NOTICE %s :No nick changes are allowed for 60 seconds because there have been more than %u nick changes in %u seconds.", channel->name.c_str(), f->nicks, f->secs);
 180                                         return MOD_RES_DENY;
 181                                 }
 182                         }
 183                 }
 184
 185                 return MOD_RES_PASSTHRU;
 186         }
 187
 188         /*
 189          * 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.
 190          */
 191         void OnUserPostNick(User* user, const std::string &oldnick)
 192         {
 193                 if (isdigit(user->nick[0])) /* allow switches to UID */
 194                         return;
 195
 196                 for (UCListIter i = user->chans.begin(); i != user->chans.end(); ++i)
 197                 {
 198                         Channel *channel = *i;
 199                         ModResult res;
 200
 201                         nickfloodsettings *f = nf.ext.get(channel);
 202                         if (f)
 203                         {
 204                                 res = ServerInstance->OnCheckExemption(user,channel,"nickflood");
 205                                 if (res == MOD_RES_ALLOW)
 206                                         return;
 207
 208                                 /* moved this here to avoid incrementing the counter for nick
 209                                  * changes that are denied for some other reason (bans, +N, etc.)
 210                                  * per bug #874.
 211                                  */
 212                                 f->addnick();
 213                         }
 214                 }
 215         }
 216
 217         ~ModuleNickFlood()
 218         {
 219         }
 220
 221         Version GetVersion()
 222         {
 223                 return Version("Channel mode F - nick flood protection", VF_VENDOR);
 224         }
 225 };
 226
 227 MODULE_INIT(ModuleNickFlood)