src/modules/m_nickflood.cpp

   1 /*       +------------------------------------+
   2  *       | Inspire Internet Relay Chat Daemon |
   3  *       +------------------------------------+
   4  *
   5  *  InspIRCd: (C) 2002-2010 InspIRCd Development Team
   6  * See: http://wiki.inspircd.org/Credits
   7  *
   8  * This program is free but copyrighted software; see
   9  *            the file COPYING for details.
  10  *
  11  * ---------------------------------------------------
  12  */
  13
  14 #include "inspircd.h"
  15
  16 /* $ModDesc: Provides channel mode +F (nick flood protection) */
  17
  18 /** Holds settings and state associated with channel mode +F
  19  */
  20 class nickfloodsettings
  21 {
  22  public:
  23         int secs;
  24         int nicks;
  25         time_t reset;
  26         time_t unlocktime;
  27         int counter;
  28         bool locked;
  29
  30         nickfloodsettings(int b, int c) : secs(b), nicks(c)
  31         {
  32                 reset = ServerInstance->Time() + secs;
  33                 counter = 0;
  34                 locked = false;
  35         };
  36
  37         void addnick()
  38         {
  39                 counter++;
  40                 if (ServerInstance->Time() > reset)
  41                 {
  42                         counter = 0;
  43                         reset = ServerInstance->Time() + secs;
  44                 }
  45         }
  46
  47         bool shouldlock()
  48         {
  49                 /* XXX HACK: using counter + 1 here now to allow the counter to only be incremented
  50                  * on successful nick changes; this will be checked before the counter is
  51                  * incremented.
  52                  */
  53                 return (counter + 1 >= this->nicks);
  54         }
  55
  56         void clear()
  57         {
  58                 counter = 0;
  59         }
  60
  61         bool islocked()
  62         {
  63                 if (locked)
  64                 {
  65                         if (ServerInstance->Time() > unlocktime)
  66                         {
  67                                 locked = false;
  68                                 return false;
  69                         }
  70                         else
  71                         {
  72                                 return true;
  73                         }
  74                 }
  75                 return false;
  76         }
  77
  78         void lock()
  79         {
  80                 locked = true;
  81                 unlocktime = ServerInstance->Time() + 60;
  82         }
  83
  84 };
  85
  86 /** Handles channel mode +j
  87  */
  88 class NickFlood : public ModeHandler
  89 {
  90  public:
  91         SimpleExtItem<nickfloodsettings> ext;
  92         NickFlood(Module* Creator) : ModeHandler(Creator, "nickflood", 'F', PARAM_SETONLY, MODETYPE_CHANNEL),
  93                 ext("nickflood", Creator) { }
  94
  95         ModeAction OnModeChange(User* source, User* dest, Channel* channel, std::string &parameter, bool adding)
  96         {
  97                 nickfloodsettings *f = ext.get(channel);
  98                 if (adding)
  99                 {
 100                         char ndata[MAXBUF];
 101                         char* data = ndata;
 102                         strlcpy(ndata,parameter.c_str(),MAXBUF);
 103                         char* nicks = data;
 104                         char* secs = NULL;
 105                         while (*data)
 106                         {
 107                                 if (*data == ':')
 108                                 {
 109                                         *data = 0;
 110                                         data++;
 111                                         secs = data;
 112                                         break;
 113                                 }
 114                                 else data++;
 115                         }
 116                         if (secs)
 117                         {
 118                                 /* Set up the flood parameters for this channel */
 119                                 int nnicks = atoi(nicks);
 120                                 int nsecs = atoi(secs);
 121                                 if ((nnicks<1) || (nsecs<1))
 122                                 {
 123                                         source->WriteNumeric(608, "%s %s :Invalid flood parameter",source->nick.c_str(),channel->name.c_str());
 124                                         parameter.clear();
 125                                         return MODEACTION_DENY;
 126                                 }
 127                                 else
 128                                 {
 129                                         if (!f)
 130                                         {
 131                                                 parameter = ConvToStr(nnicks) + ":" +ConvToStr(nsecs);
 132                                                 f = new nickfloodsettings(nsecs, nnicks);
 133                                                 ext.set(channel, f);
 134                                                 channel->SetModeParam('F', parameter);
 135                                                 return MODEACTION_ALLOW;
 136                                         }
 137                                         else
 138                                         {
 139                                                 std::string cur_param = channel->GetModeParameter('F');
 140                                                 parameter = ConvToStr(nnicks) + ":" +ConvToStr(nsecs);
 141                                                 if (cur_param == parameter)
 142                                                 {
 143                                                         // mode params match
 144                                                         return MODEACTION_DENY;
 145                                                 }
 146                                                 else
 147                                                 {
 148                                                         // new mode param, replace old with new
 149                                                         if ((nsecs > 0) && (nnicks > 0))
 150                                                         {
 151                                                                 f = new nickfloodsettings(nsecs, nnicks);
 152                                                                 ext.set(channel, f);
 153                                                                 channel->SetModeParam('F', parameter);
 154                                                                 return MODEACTION_ALLOW;
 155                                                         }
 156                                                         else
 157                                                         {
 158                                                                 return MODEACTION_DENY;
 159                                                         }
 160                                                 }
 161                                         }
 162                                 }
 163                         }
 164                         else
 165                         {
 166                                 source->WriteNumeric(608, "%s %s :Invalid flood parameter",source->nick.c_str(),channel->name.c_str());
 167                                 return MODEACTION_DENY;
 168                         }
 169                 }
 170                 else
 171                 {
 172                         if (f)
 173                         {
 174                                 ext.unset(channel);
 175                                 channel->SetModeParam('F', "");
 176                                 return MODEACTION_ALLOW;
 177                         }
 178                 }
 179                 return MODEACTION_DENY;
 180         }
 181 };
 182
 183 class ModuleNickFlood : public Module
 184 {
 185         NickFlood nf;
 186
 187  public:
 188
 189         ModuleNickFlood()
 190                 : nf(this)
 191         {
 192                 if (!ServerInstance->Modes->AddMode(&nf))
 193                         throw ModuleException("Could not add new modes!");
 194                 ServerInstance->Extensions.Register(&nf.ext);
 195                 Implementation eventlist[] = { I_OnUserPreNick, I_OnUserPostNick };
 196                 ServerInstance->Modules->Attach(eventlist, this, 2);
 197         }
 198
 199         ModResult OnUserPreNick(User* user, const std::string &newnick)
 200         {
 201                 if (ServerInstance->NICKForced.get(user)) /* Allow forced nick changes */
 202                         return MOD_RES_PASSTHRU;
 203
 204                 for (UCListIter i = user->chans.begin(); i != user->chans.end(); i++)
 205                 {
 206                         Channel *channel = *i;
 207                         ModResult res;
 208
 209                         nickfloodsettings *f = nf.ext.get(channel);
 210                         if (f)
 211                         {
 212                                 res = ServerInstance->OnCheckExemption(user,channel,"nickflood");
 213                                 if (res == MOD_RES_ALLOW)
 214                                         continue;
 215
 216                                 if (f->islocked())
 217                                 {
 218                                         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);
 219                                         return MOD_RES_DENY;
 220                                 }
 221
 222                                 if (f->shouldlock())
 223                                 {
 224                                         f->clear();
 225                                         f->lock();
 226                                         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);
 227                                         return MOD_RES_DENY;
 228                                 }
 229                         }
 230                 }
 231
 232                 return MOD_RES_PASSTHRU;
 233         }
 234
 235         /*
 236          * 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.
 237          */
 238         void OnUserPostNick(User* user, const std::string &oldnick)
 239         {
 240                 if (isdigit(user->nick[0])) /* allow switches to UID */
 241                         return;
 242
 243                 for (UCListIter i = user->chans.begin(); i != user->chans.end(); ++i)
 244                 {
 245                         Channel *channel = *i;
 246                         ModResult res;
 247
 248                         nickfloodsettings *f = nf.ext.get(channel);
 249                         if (f)
 250                         {
 251                                 res = ServerInstance->OnCheckExemption(user,channel,"nickflood");
 252                                 if (res == MOD_RES_ALLOW)
 253                                         return;
 254
 255                                 /* moved this here to avoid incrementing the counter for nick
 256                                  * changes that are denied for some other reason (bans, +N, etc.)
 257                                  * per bug #874.
 258                                  */
 259                                 f->addnick();
 260                         }
 261                 }
 262                 return;
 263         }
 264
 265         ~ModuleNickFlood()
 266         {
 267         }
 268
 269         Version GetVersion()
 270         {
 271                 return Version("Channel mode F - nick flood protection", VF_VENDOR);
 272         }
 273 };
 274
 275 MODULE_INIT(ModuleNickFlood)