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 #include "modules/exemption.h"
  23
  24 // The number of seconds nickname changing will be blocked for.
  25 static unsigned int duration;
  26
  27 /** Holds settings and state associated with channel mode +F
  28  */
  29 class nickfloodsettings
  30 {
  31  public:
  32         unsigned int secs;
  33         unsigned int nicks;
  34         time_t reset;
  35         time_t unlocktime;
  36         unsigned int counter;
  37
  38         nickfloodsettings(unsigned int b, unsigned int c)
  39                 : secs(b), nicks(c), unlocktime(0), counter(0)
  40         {
  41                 reset = ServerInstance->Time() + secs;
  42         }
  43
  44         void addnick()
  45         {
  46                 if (ServerInstance->Time() > reset)
  47                 {
  48                         counter = 1;
  49                         reset = ServerInstance->Time() + secs;
  50                 }
  51                 else
  52                         counter++;
  53         }
  54
  55         bool shouldlock()
  56         {
  57                 /* XXX HACK: using counter + 1 here now to allow the counter to only be incremented
  58                  * on successful nick changes; this will be checked before the counter is
  59                  * incremented.
  60                  */
  61                 return ((ServerInstance->Time() <= reset) && (counter == this->nicks));
  62         }
  63
  64         void clear()
  65         {
  66                 counter = 0;
  67         }
  68
  69         bool islocked()
  70         {
  71                 if (ServerInstance->Time() > unlocktime)
  72                         unlocktime = 0;
  73
  74                 return (unlocktime != 0);
  75         }
  76
  77         void lock()
  78         {
  79                 unlocktime = ServerInstance->Time() + duration;
  80         }
  81 };
  82
  83 /** Handles channel mode +F
  84  */
  85 class NickFlood : public ParamMode<NickFlood, SimpleExtItem<nickfloodsettings> >
  86 {
  87  public:
  88         NickFlood(Module* Creator)
  89                 : ParamMode<NickFlood, SimpleExtItem<nickfloodsettings> >(Creator, "nickflood", 'F')
  90         {
  91         }
  92
  93         ModeAction OnSet(User* source, Channel* channel, std::string& parameter) CXX11_OVERRIDE
  94         {
  95                 std::string::size_type colon = parameter.find(':');
  96                 if ((colon == std::string::npos) || (parameter.find('-') != std::string::npos))
  97                 {
  98                         source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter));
  99                         return MODEACTION_DENY;
 100                 }
 101
 102                 /* Set up the flood parameters for this channel */
 103                 unsigned int nnicks = ConvToNum<unsigned int>(parameter.substr(0, colon));
 104                 unsigned int nsecs = ConvToNum<unsigned int>(parameter.substr(colon+1));
 105
 106                 if ((nnicks<1) || (nsecs<1))
 107                 {
 108                         source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter));
 109                         return MODEACTION_DENY;
 110                 }
 111
 112                 ext.set(channel, new nickfloodsettings(nsecs, nnicks));
 113                 return MODEACTION_ALLOW;
 114         }
 115
 116         void SerializeParam(Channel* chan, const nickfloodsettings* nfs, std::string& out)
 117         {
 118                 out.append(ConvToStr(nfs->nicks)).push_back(':');
 119                 out.append(ConvToStr(nfs->secs));
 120         }
 121 };
 122
 123 class ModuleNickFlood : public Module
 124 {
 125         CheckExemption::EventProvider exemptionprov;
 126         NickFlood nf;
 127
 128  public:
 129         ModuleNickFlood()
 130                 : exemptionprov(this)
 131                 , nf(this)
 132         {
 133         }
 134
 135         void ReadConfig(ConfigStatus&) CXX11_OVERRIDE
 136         {
 137                 ConfigTag* tag = ServerInstance->Config->ConfValue("nickflood");
 138                 duration = tag->getDuration("duration", 60, 10, 600);
 139         }
 140
 141         ModResult OnUserPreNick(LocalUser* user, const std::string& newnick) CXX11_OVERRIDE
 142         {
 143                 for (User::ChanList::iterator i = user->chans.begin(); i != user->chans.end(); i++)
 144                 {
 145                         Channel* channel = (*i)->chan;
 146                         ModResult res;
 147
 148                         nickfloodsettings *f = nf.ext.get(channel);
 149                         if (f)
 150                         {
 151                                 res = CheckExemption::Call(exemptionprov, user, channel, "nickflood");
 152                                 if (res == MOD_RES_ALLOW)
 153                                         continue;
 154
 155                                 if (f->islocked())
 156                                 {
 157                                         user->WriteNumeric(ERR_CANTCHANGENICK, InspIRCd::Format("%s has been locked for nickchanges for %u seconds because there have been more than %u nick changes in %u seconds", channel->name.c_str(), duration, f->nicks, f->secs));
 158                                         return MOD_RES_DENY;
 159                                 }
 160
 161                                 if (f->shouldlock())
 162                                 {
 163                                         f->clear();
 164                                         f->lock();
 165                                         channel->WriteNotice(InspIRCd::Format("No nick changes are allowed for %u seconds because there have been more than %u nick changes in %u seconds.", duration, f->nicks, f->secs));
 166                                         return MOD_RES_DENY;
 167                                 }
 168                         }
 169                 }
 170
 171                 return MOD_RES_PASSTHRU;
 172         }
 173
 174         /*
 175          * 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.
 176          */
 177         void OnUserPostNick(User* user, const std::string &oldnick) CXX11_OVERRIDE
 178         {
 179                 if (isdigit(user->nick[0])) /* allow switches to UID */
 180                         return;
 181
 182                 for (User::ChanList::iterator i = user->chans.begin(); i != user->chans.end(); ++i)
 183                 {
 184                         Channel* channel = (*i)->chan;
 185                         ModResult res;
 186
 187                         nickfloodsettings *f = nf.ext.get(channel);
 188                         if (f)
 189                         {
 190                                 res = CheckExemption::Call(exemptionprov, user, channel, "nickflood");
 191                                 if (res == MOD_RES_ALLOW)
 192                                         return;
 193
 194                                 /* moved this here to avoid incrementing the counter for nick
 195                                  * changes that are denied for some other reason (bans, +N, etc.)
 196                                  * per bug #874.
 197                                  */
 198                                 f->addnick();
 199                         }
 200                 }
 201         }
 202
 203         Version GetVersion() CXX11_OVERRIDE
 204         {
 205                 return Version("Channel mode F - nick flood protection", VF_VENDOR);
 206         }
 207 };
 208
 209 MODULE_INIT(ModuleNickFlood)