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 :Channel ban list for %s is full (maximum entries for this channel is %ld)", source->nick.c_str(), channel->name.c_str(), channel->name.c_str(), maxbans);
  84                                 return false;
  85                         }
  86
  87                         for(std::string::iterator curr = start_pos; curr != param.end(); curr++)
  88                         {
  89                                 switch(*curr)
  90                                 {
  91                                         case '!':
  92                                                 mask[current].assign(start_pos, curr);
  93                                                 current = IDENT;
  94                                                 start_pos = curr+1;
  95                                                 break;
  96                                         case '@':
  97                                                 mask[current].assign(start_pos, curr);
  98                                                 current = HOST;
  99                                                 start_pos = curr+1;
 100                                                 break;
 101                                         case '#':
 102                                                 /* bug #921: don't barf when redirecting to ## channels */
 103                                                 if (current != CHAN)
 104                                                 {
 105                                                         mask[current].assign(start_pos, curr);
 106                                                         current = CHAN;
 107                                                         start_pos = curr;
 108                                                 }
 109                                                 break;
 110                                 }
 111                         }
 112
 113                         if(mask[current].empty())
 114                         {
 115                                 mask[current].assign(start_pos, param.end());
 116                         }
 117
 118                         /* nick@host wants to be changed to *!nick@host rather than nick!*@host... */
 119                         if(mask[NICK].length() && mask[HOST].length() && mask[IDENT].empty())
 120                         {
 121                                 /* std::string::swap() is fast - it runs in constant time */
 122                                 mask[NICK].swap(mask[IDENT]);
 123                         }
 124
 125                         if (!mask[NICK].empty() && mask[IDENT].empty() && mask[HOST].empty())
 126                         {
 127                                 if (mask[NICK].find('.') != std::string::npos || mask[NICK].find(':') != std::string::npos)
 128                                 {
 129                                         mask[NICK].swap(mask[HOST]);
 130                                 }
 131                         }
 132
 133                         for(int i = 0; i < 3; i++)
 134                         {
 135                                 if(mask[i].empty())
 136                                 {
 137                                         mask[i].assign("*");
 138                                 }
 139                         }
 140
 141                         param.assign(mask[NICK]).append(1, '!').append(mask[IDENT]).append(1, '@').append(mask[HOST]);
 142
 143                         if(mask[CHAN].length())
 144                         {
 145                                 if (adding && IS_LOCAL(source))
 146                                 {
 147                                         if (!ServerInstance->IsChannel(mask[CHAN].c_str(),  ServerInstance->Config->Limits.ChanMax))
 148                                         {
 149                                                 source->WriteNumeric(403, "%s %s :Invalid channel name in redirection (%s)", source->nick.c_str(), channel->name.c_str(), mask[CHAN].c_str());
 150                                                 return false;
 151                                         }
 152
 153                                         Channel *c = ServerInstance->FindChan(mask[CHAN]);
 154                                         if (!c)
 155                                         {
 156                                                 source->WriteNumeric(690, "%s :Target channel %s must exist to be set as a redirect.",source->nick.c_str(),mask[CHAN].c_str());
 157                                                 return false;
 158                                         }
 159                                         else if (adding && c->GetPrefixValue(source) < OP_VALUE)
 160                                         {
 161                                                 source->WriteNumeric(690, "%s :You must be opped on %s to set it as a redirect.",source->nick.c_str(), mask[CHAN].c_str());
 162                                                 return false;
 163                                         }
 164
 165                                         if (assign(channel->name) == mask[CHAN])
 166                                         {
 167                                                 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());
 168                                                 return false;
 169                                         }
 170                                 }
 171
 172                                 if(adding)
 173                                 {
 174                                         /* It's a properly valid redirecting ban, and we're adding it */
 175                                         redirects = extItem.get(channel);
 176                                         if (!redirects)
 177                                         {
 178                                                 redirects = new BanRedirectList;
 179                                                 extItem.set(channel, redirects);
 180                                         }
 181                                         else
 182                                         {
 183                                                 for (BanRedirectList::iterator redir = redirects->begin(); redir != redirects->end(); ++redir)
 184                                                 {
 185                                                         // Mimic the functionality used when removing the mode
 186                                                         if ((irc::string(redir->targetchan.c_str()) == irc::string(mask[CHAN].c_str())) && (irc::string(redir->banmask.c_str()) == irc::string(param.c_str())))
 187                                                         {
 188                                                                 // Make sure the +b handler will still set the right ban
 189                                                                 param.append(mask[CHAN]);
 190                                                                 // Silently ignore the duplicate and don't set metadata
 191                                                                 // This still allows channel ops to set/unset a redirect ban to clear "ghost" redirects
 192                                                                 return true;
 193                                                         }
 194                                                 }
 195                                         }
 196
 197                                         /* Here 'param' doesn't have the channel on it yet */
 198                                         redirects->push_back(BanRedirectEntry(mask[CHAN], param));
 199
 200                                         /* Now it does */
 201                                         param.append(mask[CHAN]);
 202                                 }
 203                                 else
 204                                 {
 205                                         /* Removing a ban, if there's no extensible there are no redirecting bans and we're fine. */
 206                                         redirects = extItem.get(channel);
 207                                         if (redirects)
 208                                         {
 209                                                 /* But there were, so we need to remove the matching one if there is one */
 210
 211                                                 for(BanRedirectList::iterator redir = redirects->begin(); redir != redirects->end(); redir++)
 212                                                 {
 213                                                         /* Ugly as fuck */
 214                                                         if((irc::string(redir->targetchan.c_str()) == irc::string(mask[CHAN].c_str())) && (irc::string(redir->banmask.c_str()) == irc::string(param.c_str())))
 215                                                         {
 216                                                                 redirects->erase(redir);
 217
 218                                                                 if(redirects->empty())
 219                                                                 {
 220                                                                         extItem.unset(channel);
 221                                                                 }
 222
 223                                                                 break;
 224                                                         }
 225                                                 }
 226                                         }
 227
 228                                         /* Append the channel so the default +b handler can remove the entry too */
 229                                         param.append(mask[CHAN]);
 230                                 }
 231                         }
 232                 }
 233
 234                 return true;
 235         }
 236 };
 237
 238 class ModuleBanRedirect : public Module
 239 {
 240         BanRedirect re;
 241         bool nofollow;
 242
 243  public:
 244         ModuleBanRedirect()
 245         : re(this)
 246         {
 247                 nofollow = false;
 248         }
 249
 250
 251         void init()
 252         {
 253                 if(!ServerInstance->Modes->AddModeWatcher(&re))
 254                         throw ModuleException("Could not add mode watcher");
 255
 256                 ServerInstance->Modules->AddService(re.extItem);
 257                 Implementation list[] = { I_OnUserPreJoin };
 258                 ServerInstance->Modules->Attach(list, this, sizeof(list)/sizeof(Implementation));
 259         }
 260
 261         virtual void OnCleanup(int target_type, void* item)
 262         {
 263                 if(target_type == TYPE_CHANNEL)
 264                 {
 265                         Channel* chan = static_cast<Channel*>(item);
 266                         BanRedirectList* redirects = re.extItem.get(chan);
 267
 268                         if(redirects)
 269                         {
 270                                 irc::modestacker modestack(false);
 271                                 StringDeque stackresult;
 272                                 std::vector<std::string> mode_junk;
 273                                 mode_junk.push_back(chan->name);
 274
 275                                 for(BanRedirectList::iterator i = redirects->begin(); i != redirects->end(); i++)
 276                                 {
 277                                         modestack.Push('b', i->targetchan.insert(0, i->banmask));
 278                                 }
 279
 280                                 for(BanRedirectList::iterator i = redirects->begin(); i != redirects->end(); i++)
 281                                 {
 282                                         modestack.PushPlus();
 283                                         modestack.Push('b', i->banmask);
 284                                 }
 285
 286                                 while(modestack.GetStackedLine(stackresult))
 287                                 {
 288                                         mode_junk.insert(mode_junk.end(), stackresult.begin(), stackresult.end());
 289                                         ServerInstance->SendMode(mode_junk, ServerInstance->FakeClient);
 290                                         mode_junk.erase(mode_junk.begin() + 1, mode_junk.end());
 291                                 }
 292                         }
 293                 }
 294         }
 295
 296         virtual ModResult OnUserPreJoin(User* user, Channel* chan, const char* cname, std::string &privs, const std::string &keygiven)
 297         {
 298                 if (chan)
 299                 {
 300                         BanRedirectList* redirects = re.extItem.get(chan);
 301
 302                         if (redirects)
 303                         {
 304                                 /* We actually had some ban redirects to check */
 305
 306                                 /* This was replaced with user->MakeHostIP() when I had a snprintf(), but MakeHostIP() doesn't seem to add the nick.
 307                                  * Maybe we should have a GetFullIPHost() or something to match GetFullHost() and GetFullRealHost?
 308                                  */
 309
 310                                 ModResult result;
 311                                 FIRST_MOD_RESULT(OnCheckChannelBan, result, (user, chan));
 312                                 if (result == MOD_RES_ALLOW)
 313                                 {
 314                                         // they have a ban exception
 315                                         return MOD_RES_PASSTHRU;
 316                                 }
 317
 318                                 std::string ipmask(user->nick);
 319                                 ipmask.append(1, '!').append(user->MakeHostIP());
 320
 321                                 for(BanRedirectList::iterator redir = redirects->begin(); redir != redirects->end(); redir++)
 322                                 {
 323                                         if(InspIRCd::Match(user->GetFullRealHost(), redir->banmask) || InspIRCd::Match(user->GetFullHost(), redir->banmask) || InspIRCd::MatchCIDR(ipmask, redir->banmask))
 324                                         {
 325                                                 /* This prevents recursion when a user sets multiple ban redirects in a chain
 326                                                  * (thanks Potter)
 327                                                  *
 328                                                  * If we're here and nofollow is true then we're already redirecting this user
 329                                                  * and there's a redirecting ban set on this channel that matches him, too.
 330                                                  * Deny both joins.
 331                                                  */
 332                                                 if (nofollow)
 333                                                         return MOD_RES_DENY;
 334
 335                                                 /* tell them they're banned and are being transferred */
 336                                                 Channel* destchan = ServerInstance->FindChan(redir->targetchan);
 337                                                 std::string destlimit;
 338
 339                                                 if (destchan)
 340                                                         destlimit = destchan->GetModeParameter('l');
 341
 342                                                 if(destchan && ServerInstance->Modules->Find("m_redirect.so") && destchan->IsModeSet('L') && !destlimit.empty() && (destchan->GetUserCounter() >= atoi(destlimit.c_str())))
 343                                                 {
 344                                                         user->WriteNumeric(474, "%s %s :Cannot join channel (You are banned)", user->nick.c_str(), chan->name.c_str());
 345                                                         return MOD_RES_DENY;
 346                                                 }
 347                                                 else
 348                                                 {
 349                                                         user->WriteNumeric(474, "%s %s :Cannot join channel (You are banned)", user->nick.c_str(), chan->name.c_str());
 350                                                         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());
 351                                                         nofollow = true;
 352                                                         Channel::JoinUser(user, redir->targetchan.c_str(), false, "", false, ServerInstance->Time());
 353                                                         nofollow = false;
 354                                                         return MOD_RES_DENY;
 355                                                 }
 356                                         }
 357                                 }
 358                         }
 359                 }
 360                 return MOD_RES_PASSTHRU;
 361         }
 362
 363         virtual ~ModuleBanRedirect()
 364         {
 365                 /* XXX is this the best place to do this? */
 366                 if (!ServerInstance->Modes->DelModeWatcher(&re))
 367                         ServerInstance->Logs->Log("m_banredirect.so", DEBUG, "Failed to delete modewatcher!");
 368         }
 369
 370         virtual Version GetVersion()
 371         {
 372                 return Version("Allows an extended ban (+b) syntax redirecting banned users to another channel", VF_COMMON|VF_VENDOR);
 373         }
 374 };
 375
 376 MODULE_INIT(ModuleBanRedirect)