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                 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() + duration;
  76         }
  77 };
  78
  79 /** Handles channel mode +F
  80  */
  81 class NickFlood : public ParamMode<NickFlood, SimpleExtItem<nickfloodsettings> >
  82 {
  83  public:
  84         NickFlood(Module* Creator)
  85                 : ParamMode<NickFlood, SimpleExtItem<nickfloodsettings> >(Creator, "nickflood", 'F')
  86         {
  87                 syntax = "<nick-changes>:<seconds>";
  88         }
  89
  90         ModeAction OnSet(User* source, Channel* channel, std::string& parameter) CXX11_OVERRIDE
  91         {
  92                 std::string::size_type colon = parameter.find(':');
  93                 if ((colon == std::string::npos) || (parameter.find('-') != std::string::npos))
  94                 {
  95                         source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter));
  96                         return MODEACTION_DENY;
  97                 }
  98
  99                 /* Set up the flood parameters for this channel */
 100                 unsigned int nnicks = ConvToNum<unsigned int>(parameter.substr(0, colon));
 101                 unsigned int nsecs = ConvToNum<unsigned int>(parameter.substr(colon+1));
 102
 103                 if ((nnicks<1) || (nsecs<1))
 104                 {
 105                         source->WriteNumeric(Numerics::InvalidModeParameter(channel, this, parameter));
 106                         return MODEACTION_DENY;
 107                 }
 108
 109                 ext.set(channel, new nickfloodsettings(nsecs, nnicks));
 110                 return MODEACTION_ALLOW;
 111         }
 112
 113         void SerializeParam(Channel* chan, const nickfloodsettings* nfs, std::string& out)
 114         {
 115                 out.append(ConvToStr(nfs->nicks)).push_back(':');
 116                 out.append(ConvToStr(nfs->secs));
 117         }
 118 };
 119
 120 class ModuleNickFlood : public Module
 121 {
 122         CheckExemption::EventProvider exemptionprov;
 123         NickFlood nf;
 124
 125  public:
 126         ModuleNickFlood()
 127                 : exemptionprov(this)
 128                 , nf(this)
 129         {
 130         }
 131
 132         void ReadConfig(ConfigStatus&) CXX11_OVERRIDE
 133         {
 134                 ConfigTag* tag = ServerInstance->Config->ConfValue("nickflood");
 135                 duration = tag->getDuration("duration", 60, 10, 600);
 136         }
 137
 138         ModResult OnUserPreNick(LocalUser* user, const std::string& newnick) CXX11_OVERRIDE
 139         {
 140                 for (User::ChanList::iterator i = user->chans.begin(); i != user->chans.end(); i++)
 141                 {
 142                         Channel* channel = (*i)->chan;
 143                         ModResult res;
 144
 145                         nickfloodsettings *f = nf.ext.get(channel);
 146                         if (f)
 147                         {
 148                                 res = CheckExemption::Call(exemptionprov, user, channel, "nickflood");
 149                                 if (res == MOD_RES_ALLOW)
 150                                         continue;
 151
 152                                 if (f->islocked())
 153                                 {
 154                                         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));
 155                                         return MOD_RES_DENY;
 156                                 }
 157
 158                                 if (f->shouldlock())
 159                                 {
 160                                         f->clear();
 161                                         f->lock();
 162                                         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));
 163                                         return MOD_RES_DENY;
 164                                 }
 165                         }
 166                 }
 167
 168                 return MOD_RES_PASSTHRU;
 169         }
 170
 171         /*
 172          * 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.
 173          */
 174         void OnUserPostNick(User* user, const std::string &oldnick) CXX11_OVERRIDE
 175         {
 176                 if (isdigit(user->nick[0])) /* allow switches to UID */
 177                         return;
 178
 179                 for (User::ChanList::iterator i = user->chans.begin(); i != user->chans.end(); ++i)
 180                 {
 181                         Channel* channel = (*i)->chan;
 182                         ModResult res;
 183
 184                         nickfloodsettings *f = nf.ext.get(channel);
 185                         if (f)
 186                         {
 187                                 res = CheckExemption::Call(exemptionprov, user, channel, "nickflood");
 188                                 if (res == MOD_RES_ALLOW)
 189                                         return;
 190
 191                                 /* moved this here to avoid incrementing the counter for nick
 192                                  * changes that are denied for some other reason (bans, +N, etc.)
 193                                  * per bug #874.
 194                                  */
 195                                 f->addnick();
 196                         }
 197                 }
 198         }
 199
 200         Version GetVersion() CXX11_OVERRIDE
 201         {
 202                 return Version("Provides channel mode +F, nick flood protection", VF_VENDOR);
 203         }
 204 };
 205
 206 MODULE_INIT(ModuleNickFlood)