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 /** Holds settings and state associated with channel mode +F
  24  */
  25 class nickfloodsettings
  26 {
  27  public:
  28         unsigned int secs;
  29         unsigned int nicks;
  30         time_t reset;
  31         time_t unlocktime;
  32         unsigned int counter;
  33
  34         nickfloodsettings(unsigned int b, unsigned int c)
  35                 : secs(b), nicks(c), unlocktime(0), counter(0)
  36         {
  37                 reset = ServerInstance->Time() + secs;
  38         }
  39
  40         void addnick()
  41         {
  42                 if (ServerInstance->Time() > reset)
  43                 {
  44                         counter = 1;
  45                         reset = ServerInstance->Time() + secs;
  46                 }
  47                 else
  48                         counter++;
  49         }
  50
  51         bool shouldlock()
  52         {
  53                 /* XXX HACK: using counter + 1 here now to allow the counter to only be incremented
  54                  * on successful nick changes; this will be checked before the counter is
  55                  * incremented.
  56                  */
  57                 return ((ServerInstance->Time() <= reset) && (counter == this->nicks));
  58         }
  59
  60         void clear()
  61         {
  62                 counter = 0;
  63         }
  64
  65         bool islocked()
  66         {
  67                 if (ServerInstance->Time() > unlocktime)
  68                         unlocktime = 0;
  69
  70                 return (unlocktime != 0);
  71         }
  72
  73         void lock()
  74         {
  75                 unlocktime = ServerInstance->Time() + 60;
  76         }
  77 };
  78
  79 /** Handles channel mode +F
  80  */
  81 class NickFlood : public ModeHandler
  82 {
  83  public:
  84         SimpleExtItem<nickfloodsettings> ext;
  85         NickFlood(Module* Creator) : ModeHandler(Creator, "nickflood", 'F', PARAM_SETONLY, MODETYPE_CHANNEL),
  86                 ext("nickflood", Creator) { }
  87
  88         ModeAction OnModeChange(User* source, User* dest, Channel* channel, std::string &parameter, bool adding)
  89         {
  90                 if (adding)
  91                 {
  92                         std::string::size_type colon = parameter.find(':');
  93                         if ((colon == std::string::npos) || (parameter.find('-') != std::string::npos))
  94                         {
  95                                 source->WriteNumeric(608, "%s :Invalid flood parameter",channel->name.c_str());
  96                                 return MODEACTION_DENY;
  97                         }
  98
  99                         /* Set up the flood parameters for this channel */
 100                         unsigned int nnicks = ConvToInt(parameter.substr(0, colon));
 101                         unsigned int nsecs = ConvToInt(parameter.substr(colon+1));
 102
 103                         if ((nnicks<1) || (nsecs<1))
 104                         {
 105                                 source->WriteNumeric(608, "%s :Invalid flood parameter",channel->name.c_str());
 106                                 return MODEACTION_DENY;
 107                         }
 108
 109                         nickfloodsettings* f = ext.get(channel);
 110                         if ((f) && (nnicks == f->nicks) && (nsecs == f->secs))
 111                                 // mode params match
 112                                 return MODEACTION_DENY;
 113
 114                         ext.set(channel, new nickfloodsettings(nsecs, nnicks));
 115                         parameter = ConvToStr(nnicks) + ":" + ConvToStr(nsecs);
 116                         return MODEACTION_ALLOW;
 117                 }
 118                 else
 119                 {
 120                         if (!channel->IsModeSet(this))
 121                                 return MODEACTION_DENY;
 122
 123                         ext.unset(channel);
 124                         return MODEACTION_ALLOW;
 125                 }
 126         }
 127 };
 128
 129 class ModuleNickFlood : public Module
 130 {
 131         NickFlood nf;
 132
 133  public:
 134         ModuleNickFlood()
 135                 : nf(this)
 136         {
 137         }
 138
 139         ModResult OnUserPreNick(User* user, const std::string &newnick) CXX11_OVERRIDE
 140         {
 141                 for (UCListIter i = user->chans.begin(); i != user->chans.end(); i++)
 142                 {
 143                         Channel* channel = (*i)->chan;
 144                         ModResult res;
 145
 146                         nickfloodsettings *f = nf.ext.get(channel);
 147                         if (f)
 148                         {
 149                                 res = ServerInstance->OnCheckExemption(user,channel,"nickflood");
 150                                 if (res == MOD_RES_ALLOW)
 151                                         continue;
 152
 153                                 if (f->islocked())
 154                                 {
 155                                         user->WriteNumeric(ERR_CANTCHANGENICK, ":%s has been locked for nickchanges for 60 seconds because there have been more than %u nick changes in %u seconds", channel->name.c_str(), f->nicks, f->secs);
 156                                         return MOD_RES_DENY;
 157                                 }
 158
 159                                 if (f->shouldlock())
 160                                 {
 161                                         f->clear();
 162                                         f->lock();
 163                                         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);
 164                                         return MOD_RES_DENY;
 165                                 }
 166                         }
 167                 }
 168
 169                 return MOD_RES_PASSTHRU;
 170         }
 171
 172         /*
 173          * 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.
 174          */
 175         void OnUserPostNick(User* user, const std::string &oldnick) CXX11_OVERRIDE
 176         {
 177                 if (isdigit(user->nick[0])) /* allow switches to UID */
 178                         return;
 179
 180                 for (UCListIter i = user->chans.begin(); i != user->chans.end(); ++i)
 181                 {
 182                         Channel* channel = (*i)->chan;
 183                         ModResult res;
 184
 185                         nickfloodsettings *f = nf.ext.get(channel);
 186                         if (f)
 187                         {
 188                                 res = ServerInstance->OnCheckExemption(user,channel,"nickflood");
 189                                 if (res == MOD_RES_ALLOW)
 190                                         return;
 191
 192                                 /* moved this here to avoid incrementing the counter for nick
 193                                  * changes that are denied for some other reason (bans, +N, etc.)
 194                                  * per bug #874.
 195                                  */
 196                                 f->addnick();
 197                         }
 198                 }
 199         }
 200
 201         Version GetVersion() CXX11_OVERRIDE
 202         {
 203                 return Version("Channel mode F - nick flood protection", VF_VENDOR);
 204         }
 205 };
 206
 207 MODULE_INIT(ModuleNickFlood)