src/modules/m_banredirect.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  *   Copyright (C) 2008 Pippijn van Steenhoven <pip88nl@gmail.com>
   7  *   Copyright (C) 2007 Dennis Friis <peavey@inspircd.org>
   8  *   Copyright (C) 2007 Craig Edwards <craigedwards@brainbox.cc>
   9  *   Copyright (C) 2007 Oliver Lupton <oliverlupton@gmail.com>
  10  *
  11  * This file is part of InspIRCd.  InspIRCd is free software: you can
  12  * redistribute it and/or modify it under the terms of the GNU General Public
  13  * License as published by the Free Software Foundation, version 2.
  14  *
  15  * This program is distributed in the hope that it will be useful, but WITHOUT
  16  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  17  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  18  * details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22  */
  23
  24
  25 #include "inspircd.h"
  26 #include "u_listmode.h"
  27
  28 /* $ModDesc: Allows an extended ban (+b) syntax redirecting banned users to another channel */
  29
  30 /* Originally written by Om, January 2009
  31  */
  32
  33 class BanRedirectEntry
  34 {
  35  public:
  36         std::string targetchan;
  37         std::string banmask;
  38
  39         BanRedirectEntry(const std::string &target = "", const std::string &mask = "")
  40         : targetchan(target), banmask(mask)
  41         {
  42         }
  43 };
  44
  45 typedef std::vector<BanRedirectEntry> BanRedirectList;
  46 typedef std::deque<std::string> StringDeque;
  47
  48 class BanRedirect : public ModeWatcher
  49 {
  50  public:
  51         SimpleExtItem<BanRedirectList> extItem;
  52         BanRedirect(Module* parent) : ModeWatcher(parent, 'b', MODETYPE_CHANNEL),
  53                 extItem("banredirect", parent)
  54         {
  55         }
  56
  57         bool BeforeMode(User* source, User* dest, Channel* channel, std::string &param, bool adding, ModeType type)
  58         {
  59                 /* nick!ident@host -> nick!ident@host
  60                  * nick!ident@host#chan -> nick!ident@host#chan
  61                  * nick@host#chan -> nick!*@host#chan
  62                  * nick!ident#chan -> nick!ident@*#chan
  63                  * nick#chan -> nick!*@*#chan
  64                  */
  65
  66                 if(channel && (type == MODETYPE_CHANNEL) && param.length())
  67                 {
  68                         BanRedirectList* redirects;
  69
  70                         std::string mask[4];
  71                         enum { NICK, IDENT, HOST, CHAN } current = NICK;
  72                         std::string::iterator start_pos = param.begin();
  73                         long maxbans = channel->GetMaxBans();
  74
  75                         if (param.length() >= 2 && param[1] == ':')
  76                                 return true;
  77
  78                         if (param.find('#') == std::string::npos)
  79                                 return true;
  80
  81                         if(adding && (channel->bans.size() > static_cast<unsigned>(maxbans)))
  82                         {
  83                                 source->WriteNumeric(478, "%s %s %c :Channel ban list for %s is full (maximum entries for this channel is %ld)",
  84                                         source->nick.c_str(), channel->name.c_str(), mode, channel->name.c_str(), maxbans);
  85                                 return false;
  86                         }
  87
  88                         for(std::string::iterator curr = start_pos; curr != param.end(); curr++)
  89                         {
  90                                 switch(*curr)
  91                                 {
  92                                         case '!':
  93                                                 mask[current].assign(start_pos, curr);
  94                                                 current = IDENT;
  95                                                 start_pos = curr+1;
  96                                                 break;
  97                                         case '@':
  98                                                 mask[current].assign(start_pos, curr);
  99                                                 current = HOST;
 100                                                 start_pos = curr+1;
 101                                                 break;
 102                                         case '#':
 103                                                 /* bug #921: don't barf when redirecting to ## channels */
 104                                                 if (current != CHAN)
 105                                                 {
 106                                                         mask[current].assign(start_pos, curr);
 107                                                         current = CHAN;
 108                                                         start_pos = curr;
 109                                                 }
 110                                                 break;
 111                                 }
 112                         }
 113
 114                         if(mask[current].empty())
 115                         {
 116                                 mask[current].assign(start_pos, param.end());
 117                         }
 118
 119                         /* nick@host wants to be changed to *!nick@host rather than nick!*@host... */
 120                         if(mask[NICK].length() && mask[HOST].length() && mask[IDENT].empty())
 121                         {
 122                                 /* std::string::swap() is fast - it runs in constant time */
 123                                 mask[NICK].swap(mask[IDENT]);
 124                         }
 125
 126                         if (!mask[NICK].empty() && mask[IDENT].empty() && mask[HOST].empty())
 127                         {
 128                                 if (mask[NICK].find('.') != std::string::npos || mask[NICK].find(':') != std::string::npos)
 129                                 {
 130                                         mask[NICK].swap(mask[HOST]);
 131                                 }
 132                         }
 133
 134                         for(int i = 0; i < 3; i++)
 135                         {
 136                                 if(mask[i].empty())
 137                                 {
 138                                         mask[i].assign("*");
 139                                 }
 140                         }
 141
 142                         param.assign(mask[NICK]).append(1, '!').append(mask[IDENT]).append(1, '@').append(mask[HOST]);
 143
 144                         if(mask[CHAN].length())
 145                         {
 146                                 if (adding && IS_LOCAL(source))
 147                                 {
 148                                         if (!ServerInstance->IsChannel(mask[CHAN].c_str(),  ServerInstance->Config->Limits.ChanMax))
 149                                         {
 150                                                 source->WriteNumeric(403, "%s %s :Invalid channel name in redirection (%s)", source->nick.c_str(), channel->name.c_str(), mask[CHAN].c_str());
 151                                                 return false;
 152                                         }
 153
 154                                         Channel *c = ServerInstance->FindChan(mask[CHAN]);
 155                                         if (!c)
 156                                         {
 157                                                 source->WriteNumeric(690, "%s :Target channel %s must exist to be set as a redirect.",source->nick.c_str(),mask[CHAN].c_str());
 158                                                 return false;
 159                                         }
 160                                         else if (adding && c->GetPrefixValue(source) < OP_VALUE)
 161                                         {
 162                                                 source->WriteNumeric(690, "%s :You must be opped on %s to set it as a redirect.",source->nick.c_str(), mask[CHAN].c_str());
 163                                                 return false;
 164                                         }
 165
 166                                         if (assign(channel->name) == mask[CHAN])
 167                                         {
 168                                                 source->WriteNumeric(690, "%s %s :You cannot set a ban redirection to the channel the ban is on", source->nick.c_str(), channel->name.c_str());
 169                                                 return false;
 170                                         }
 171                                 }
 172
 173                                 if(adding)
 174                                 {
 175                                         /* It's a properly valid redirecting ban, and we're adding it */
 176                                         redirects = extItem.get(channel);
 177                                         if (!redirects)
 178                                         {
 179                                                 redirects = new BanRedirectList;
 180                                                 extItem.set(channel, redirects);
 181                                         }
 182                                         else
 183                                         {
 184                                                 for (BanRedirectList::iterator redir = redirects->begin(); redir != redirects->end(); ++redir)
 185                                                 {
 186                                                         // Mimic the functionality used when removing the mode
 187                                                         if ((irc::string(redir->targetchan.c_str()) == irc::string(mask[CHAN].c_str())) && (irc::string(redir->banmask.c_str()) == irc::string(param.c_str())))
 188                                                         {
 189                                                                 // Make sure the +b handler will still set the right ban
 190                                                                 param.append(mask[CHAN]);
 191                                                                 // Silently ignore the duplicate and don't set metadata
 192                                                                 // This still allows channel ops to set/unset a redirect ban to clear "ghost" redirects
 193                                                                 return true;
 194                                                         }
 195                                                 }
 196                                         }
 197
 198                                         /* Here 'param' doesn't have the channel on it yet */
 199                                         redirects->push_back(BanRedirectEntry(mask[CHAN], param));
 200
 201                                         /* Now it does */
 202                                         param.append(mask[CHAN]);
 203                                 }
 204                                 else
 205                                 {
 206                                         /* Removing a ban, if there's no extensible there are no redirecting bans and we're fine. */
 207                                         redirects = extItem.get(channel);
 208                                         if (redirects)
 209                                         {
 210                                                 /* But there were, so we need to remove the matching one if there is one */
 211
 212                                                 for(BanRedirectList::iterator redir = redirects->begin(); redir != redirects->end(); redir++)
 213                                                 {
 214                                                         /* Ugly as fuck */
 215                                                         if((irc::string(redir->targetchan.c_str()) == irc::string(mask[CHAN].c_str())) && (irc::string(redir->banmask.c_str()) == irc::string(param.c_str())))
 216                                                         {
 217                                                                 redirects->erase(redir);
 218
 219                                                                 if(redirects->empty())
 220                                                                 {
 221                                                                         extItem.unset(channel);
 222                                                                 }
 223
 224                                                                 break;
 225                                                         }
 226                                                 }
 227                                         }
 228
 229                                         /* Append the channel so the default +b handler can remove the entry too */
 230                                         param.append(mask[CHAN]);
 231                                 }
 232                         }
 233                 }
 234
 235                 return true;
 236         }
 237 };
 238
 239 class ModuleBanRedirect : public Module
 240 {
 241         BanRedirect re;
 242         bool nofollow;
 243
 244  public:
 245         ModuleBanRedirect()
 246         : re(this)
 247         {
 248                 nofollow = false;
 249         }
 250
 251
 252         void init()
 253         {
 254                 if(!ServerInstance->Modes->AddModeWatcher(&re))
 255                         throw ModuleException("Could not add mode watcher");
 256
 257                 ServerInstance->Modules->AddService(re.extItem);
 258                 Implementation list[] = { I_OnUserPreJoin };
 259                 ServerInstance->Modules->Attach(list, this, sizeof(list)/sizeof(Implementation));
 260         }
 261
 262         virtual void OnCleanup(int target_type, void* item)
 263         {
 264                 if(target_type == TYPE_CHANNEL)
 265                 {
 266                         Channel* chan = static_cast<Channel*>(item);
 267                         BanRedirectList* redirects = re.extItem.get(chan);
 268
 269                         if(redirects)
 270                         {
 271                                 irc::modestacker modestack(false);
 272                                 StringDeque stackresult;
 273                                 std::vector<std::string> mode_junk;
 274                                 mode_junk.push_back(chan->name);
 275
 276                                 for(BanRedirectList::iterator i = redirects->begin(); i != redirects->end(); i++)
 277                                 {
 278                                         modestack.Push('b', i->targetchan.insert(0, i->banmask));
 279                                 }
 280
 281                                 for(BanRedirectList::iterator i = redirects->begin(); i != redirects->end(); i++)
 282                                 {
 283                                         modestack.PushPlus();
 284                                         modestack.Push('b', i->banmask);
 285                                 }
 286
 287                                 while(modestack.GetStackedLine(stackresult))
 288                                 {
 289                                         mode_junk.insert(mode_junk.end(), stackresult.begin(), stackresult.end());
 290                                         ServerInstance->SendMode(mode_junk, ServerInstance->FakeClient);
 291                                         mode_junk.erase(mode_junk.begin() + 1, mode_junk.end());
 292                                 }
 293                         }
 294                 }
 295         }
 296
 297         virtual ModResult OnUserPreJoin(User* user, Channel* chan, const char* cname, std::string &privs, const std::string &keygiven)
 298         {
 299                 if (chan)
 300                 {
 301                         BanRedirectList* redirects = re.extItem.get(chan);
 302
 303                         if (redirects)
 304                         {
 305                                 /* We actually had some ban redirects to check */
 306
 307                                 /* This was replaced with user->MakeHostIP() when I had a snprintf(), but MakeHostIP() doesn't seem to add the nick.
 308                                  * Maybe we should have a GetFullIPHost() or something to match GetFullHost() and GetFullRealHost?
 309                                  */
 310
 311                                 ModResult result;
 312                                 FIRST_MOD_RESULT(OnCheckChannelBan, result, (user, chan));
 313                                 if (result == MOD_RES_ALLOW)
 314                                 {
 315                                         // they have a ban exception
 316                                         return MOD_RES_PASSTHRU;
 317                                 }
 318
 319                                 std::string ipmask(user->nick);
 320                                 ipmask.append(1, '!').append(user->MakeHostIP());
 321
 322                                 for(BanRedirectList::iterator redir = redirects->begin(); redir != redirects->end(); redir++)
 323                                 {
 324                                         if(InspIRCd::Match(user->GetFullRealHost(), redir->banmask) || InspIRCd::Match(user->GetFullHost(), redir->banmask) || InspIRCd::MatchCIDR(ipmask, redir->banmask))
 325                                         {
 326                                                 /* This prevents recursion when a user sets multiple ban redirects in a chain
 327                                                  * (thanks Potter)
 328                                                  *
 329                                                  * If we're here and nofollow is true then we're already redirecting this user
 330                                                  * and there's a redirecting ban set on this channel that matches him, too.
 331                                                  * Deny both joins.
 332                                                  */
 333                                                 if (nofollow)
 334                                                         return MOD_RES_DENY;
 335
 336                                                 /* tell them they're banned and are being transferred */
 337                                                 Channel* destchan = ServerInstance->FindChan(redir->targetchan);
 338                                                 std::string destlimit;
 339
 340                                                 if (destchan)
 341                                                         destlimit = destchan->GetModeParameter('l');
 342
 343                                                 if(destchan && ServerInstance->Modules->Find("m_redirect.so") && destchan->IsModeSet('L') && !destlimit.empty() && (destchan->GetUserCounter() >= atoi(destlimit.c_str())))
 344                                                 {
 345                                                         user->WriteNumeric(474, "%s %s :Cannot join channel (You are banned)", user->nick.c_str(), chan->name.c_str());
 346                                                         return MOD_RES_DENY;
 347                                                 }
 348                                                 else
 349                                                 {
 350                                                         user->WriteNumeric(474, "%s %s :Cannot join channel (You are banned)", user->nick.c_str(), chan->name.c_str());
 351                                                         user->WriteNumeric(470, "%s %s %s :You are banned from this channel, so you are automatically transferred to the redirected channel.", user->nick.c_str(), chan->name.c_str(), redir->targetchan.c_str());
 352                                                         nofollow = true;
 353                                                         Channel::JoinUser(user, redir->targetchan.c_str(), false, "", false, ServerInstance->Time());
 354                                                         nofollow = false;
 355                                                         return MOD_RES_DENY;
 356                                                 }
 357                                         }
 358                                 }
 359                         }
 360                 }
 361                 return MOD_RES_PASSTHRU;
 362         }
 363
 364         virtual ~ModuleBanRedirect()
 365         {
 366                 /* XXX is this the best place to do this? */
 367                 if (!ServerInstance->Modes->DelModeWatcher(&re))
 368                         ServerInstance->Logs->Log("m_banredirect.so", DEBUG, "Failed to delete modewatcher!");
 369         }
 370
 371         virtual Version GetVersion()
 372         {
 373                 return Version("Allows an extended ban (+b) syntax redirecting banned users to another channel", VF_COMMON|VF_VENDOR);
 374         }
 375 };
 376
 377 MODULE_INIT(ModuleBanRedirect)