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 "listmode.h"
  27
  28 /* Originally written by Om, January 2009
  29  */
  30
  31 class BanRedirectEntry
  32 {
  33  public:
  34         std::string targetchan;
  35         std::string banmask;
  36
  37         BanRedirectEntry(const std::string &target = "", const std::string &mask = "")
  38         : targetchan(target), banmask(mask)
  39         {
  40         }
  41 };
  42
  43 typedef std::vector<BanRedirectEntry> BanRedirectList;
  44
  45 class BanRedirect : public ModeWatcher
  46 {
  47         ChanModeReference ban;
  48  public:
  49         SimpleExtItem<BanRedirectList> extItem;
  50         BanRedirect(Module* parent)
  51                 : ModeWatcher(parent, "ban", MODETYPE_CHANNEL)
  52                 , ban(parent, "ban")
  53                 , extItem("banredirect", ExtensionItem::EXT_CHANNEL, parent)
  54         {
  55         }
  56
  57         bool BeforeMode(User* source, User* dest, Channel* channel, std::string& param, bool adding) CXX11_OVERRIDE
  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) && !param.empty())
  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
  74                         if (param.length() >= 2 && param[1] == ':')
  75                                 return true;
  76
  77                         if (param.find('#') == std::string::npos)
  78                                 return true;
  79
  80                         ListModeBase* banlm = static_cast<ListModeBase*>(*ban);
  81                         unsigned int maxbans = banlm->GetLimit(channel);
  82                         ListModeBase::ModeList* list = banlm->GetList(channel);
  83                         if ((list) && (adding) && (maxbans <= list->size()))
  84                         {
  85                                 source->WriteNumeric(ERR_BANLISTFULL, channel->name, banlm->GetModeChar(), InspIRCd::Format("Channel ban list for %s is full (maximum entries for this channel is %u)", channel->name.c_str(), maxbans));
  86                                 return false;
  87                         }
  88
  89                         for(std::string::iterator curr = start_pos; curr != param.end(); curr++)
  90                         {
  91                                 switch(*curr)
  92                                 {
  93                                         case '!':
  94                                                 if (current != NICK)
  95                                                         break;
  96                                                 mask[current].assign(start_pos, curr);
  97                                                 current = IDENT;
  98                                                 start_pos = curr+1;
  99                                                 break;
 100                                         case '@':
 101                                                 if (current != IDENT)
 102                                                         break;
 103                                                 mask[current].assign(start_pos, curr);
 104                                                 current = HOST;
 105                                                 start_pos = curr+1;
 106                                                 break;
 107                                         case '#':
 108                                                 if (current == CHAN)
 109                                                         break;
 110                                                 mask[current].assign(start_pos, curr);
 111                                                 current = CHAN;
 112                                                 start_pos = curr;
 113                                                 break;
 114                                 }
 115                         }
 116
 117                         if(mask[current].empty())
 118                         {
 119                                 mask[current].assign(start_pos, param.end());
 120                         }
 121
 122                         /* nick@host wants to be changed to *!nick@host rather than nick!*@host... */
 123                         if(mask[NICK].length() && mask[HOST].length() && mask[IDENT].empty())
 124                         {
 125                                 /* std::string::swap() is fast - it runs in constant time */
 126                                 mask[NICK].swap(mask[IDENT]);
 127                         }
 128
 129                         if (!mask[NICK].empty() && mask[IDENT].empty() && mask[HOST].empty())
 130                         {
 131                                 if (mask[NICK].find('.') != std::string::npos || mask[NICK].find(':') != std::string::npos)
 132                                 {
 133                                         mask[NICK].swap(mask[HOST]);
 134                                 }
 135                         }
 136
 137                         for(int i = 0; i < 3; i++)
 138                         {
 139                                 if(mask[i].empty())
 140                                 {
 141                                         mask[i].assign("*");
 142                                 }
 143                         }
 144
 145                         param.assign(mask[NICK]).append(1, '!').append(mask[IDENT]).append(1, '@').append(mask[HOST]);
 146
 147                         if(mask[CHAN].length())
 148                         {
 149                                 if (adding && IS_LOCAL(source))
 150                                 {
 151                                         if (!ServerInstance->IsChannel(mask[CHAN]))
 152                                         {
 153                                                 source->WriteNumeric(ERR_NOSUCHCHANNEL, channel->name, InspIRCd::Format("Invalid channel name in redirection (%s)", mask[CHAN].c_str()));
 154                                                 return false;
 155                                         }
 156
 157                                         Channel *c = ServerInstance->FindChan(mask[CHAN]);
 158                                         if (!c)
 159                                         {
 160                                                 source->WriteNumeric(690, InspIRCd::Format("Target channel %s must exist to be set as a redirect.", mask[CHAN].c_str()));
 161                                                 return false;
 162                                         }
 163                                         else if (adding && c->GetPrefixValue(source) < OP_VALUE)
 164                                         {
 165                                                 source->WriteNumeric(690, InspIRCd::Format("You must be opped on %s to set it as a redirect.", mask[CHAN].c_str()));
 166                                                 return false;
 167                                         }
 168
 169                                         if (irc::equals(channel->name, mask[CHAN]))
 170                                         {
 171                                                 source->WriteNumeric(690, channel->name, "You cannot set a ban redirection to the channel the ban is on");
 172                                                 return false;
 173                                         }
 174                                 }
 175
 176                                 if(adding)
 177                                 {
 178                                         /* It's a properly valid redirecting ban, and we're adding it */
 179                                         redirects = extItem.get(channel);
 180                                         if (!redirects)
 181                                         {
 182                                                 redirects = new BanRedirectList;
 183                                                 extItem.set(channel, redirects);
 184                                         }
 185                                         else
 186                                         {
 187                                                 for (BanRedirectList::iterator redir = redirects->begin(); redir != redirects->end(); ++redir)
 188                                                 {
 189                                                         // Mimic the functionality used when removing the mode
 190                                                         if (irc::equals(redir->targetchan, mask[CHAN]) && irc::equals(redir->banmask, param))
 191                                                         {
 192                                                                 // Make sure the +b handler will still set the right ban
 193                                                                 param.append(mask[CHAN]);
 194                                                                 // Silently ignore the duplicate and don't set metadata
 195                                                                 // This still allows channel ops to set/unset a redirect ban to clear "ghost" redirects
 196                                                                 return true;
 197                                                         }
 198                                                 }
 199                                         }
 200
 201                                         /* Here 'param' doesn't have the channel on it yet */
 202                                         redirects->push_back(BanRedirectEntry(mask[CHAN], param));
 203
 204                                         /* Now it does */
 205                                         param.append(mask[CHAN]);
 206                                 }
 207                                 else
 208                                 {
 209                                         /* Removing a ban, if there's no extensible there are no redirecting bans and we're fine. */
 210                                         redirects = extItem.get(channel);
 211                                         if (redirects)
 212                                         {
 213                                                 /* But there were, so we need to remove the matching one if there is one */
 214
 215                                                 for(BanRedirectList::iterator redir = redirects->begin(); redir != redirects->end(); redir++)
 216                                                 {
 217                                                         if ((irc::equals(redir->targetchan, mask[CHAN])) && (irc::equals(redir->banmask, param)))
 218                                                         {
 219                                                                 redirects->erase(redir);
 220
 221                                                                 if(redirects->empty())
 222                                                                 {
 223                                                                         extItem.unset(channel);
 224                                                                 }
 225
 226                                                                 break;
 227                                                         }
 228                                                 }
 229                                         }
 230
 231                                         /* Append the channel so the default +b handler can remove the entry too */
 232                                         param.append(mask[CHAN]);
 233                                 }
 234                         }
 235                 }
 236
 237                 return true;
 238         }
 239 };
 240
 241 class ModuleBanRedirect : public Module
 242 {
 243         BanRedirect re;
 244         bool nofollow;
 245         ChanModeReference limitmode;
 246         ChanModeReference redirectmode;
 247
 248  public:
 249         ModuleBanRedirect()
 250                 : re(this)
 251                 , nofollow(false)
 252                 , limitmode(this, "limit")
 253                 , redirectmode(this, "redirect")
 254         {
 255         }
 256
 257         void OnCleanup(ExtensionItem::ExtensibleType type, Extensible* item) CXX11_OVERRIDE
 258         {
 259                 if (type == ExtensionItem::EXT_CHANNEL)
 260                 {
 261                         Channel* chan = static_cast<Channel*>(item);
 262                         BanRedirectList* redirects = re.extItem.get(chan);
 263
 264                         if(redirects)
 265                         {
 266                                 ModeHandler* ban = ServerInstance->Modes->FindMode('b', MODETYPE_CHANNEL);
 267                                 Modes::ChangeList changelist;
 268
 269                                 for(BanRedirectList::iterator i = redirects->begin(); i != redirects->end(); i++)
 270                                         changelist.push_remove(ban, i->targetchan.insert(0, i->banmask));
 271
 272                                 for(BanRedirectList::iterator i = redirects->begin(); i != redirects->end(); i++)
 273                                         changelist.push_add(ban, i->banmask);
 274
 275                                 ServerInstance->Modes->Process(ServerInstance->FakeClient, chan, NULL, changelist, ModeParser::MODE_LOCALONLY);
 276                         }
 277                 }
 278         }
 279
 280         ModResult OnUserPreJoin(LocalUser* user, Channel* chan, const std::string& cname, std::string& privs, const std::string& keygiven) CXX11_OVERRIDE
 281         {
 282                 if (chan)
 283                 {
 284                         BanRedirectList* redirects = re.extItem.get(chan);
 285
 286                         if (redirects)
 287                         {
 288                                 /* We actually had some ban redirects to check */
 289
 290                                 /* This was replaced with user->MakeHostIP() when I had a snprintf(), but MakeHostIP() doesn't seem to add the nick.
 291                                  * Maybe we should have a GetFullIPHost() or something to match GetFullHost() and GetFullRealHost?
 292                                  */
 293
 294                                 ModResult result;
 295                                 FIRST_MOD_RESULT(OnCheckChannelBan, result, (user, chan));
 296                                 if (result == MOD_RES_ALLOW)
 297                                 {
 298                                         // they have a ban exception
 299                                         return MOD_RES_PASSTHRU;
 300                                 }
 301
 302                                 std::string ipmask(user->nick);
 303                                 ipmask.append(1, '!').append(user->MakeHostIP());
 304
 305                                 for(BanRedirectList::iterator redir = redirects->begin(); redir != redirects->end(); redir++)
 306                                 {
 307                                         if(InspIRCd::Match(user->GetFullRealHost(), redir->banmask) || InspIRCd::Match(user->GetFullHost(), redir->banmask) || InspIRCd::MatchCIDR(ipmask, redir->banmask))
 308                                         {
 309                                                 /* This prevents recursion when a user sets multiple ban redirects in a chain
 310                                                  * (thanks Potter)
 311                                                  *
 312                                                  * If we're here and nofollow is true then we're already redirecting this user
 313                                                  * and there's a redirecting ban set on this channel that matches him, too.
 314                                                  * Deny both joins.
 315                                                  */
 316                                                 if (nofollow)
 317                                                         return MOD_RES_DENY;
 318
 319                                                 /* tell them they're banned and are being transferred */
 320                                                 Channel* destchan = ServerInstance->FindChan(redir->targetchan);
 321                                                 std::string destlimit;
 322
 323                                                 if (destchan)
 324                                                         destlimit = destchan->GetModeParameter(limitmode);
 325
 326                                                 if(destchan && destchan->IsModeSet(redirectmode) && !destlimit.empty() && (destchan->GetUserCounter() >= ConvToNum<size_t>(destlimit)))
 327                                                 {
 328                                                         user->WriteNumeric(ERR_BANNEDFROMCHAN, chan->name, "Cannot join channel (you're banned)");
 329                                                         return MOD_RES_DENY;
 330                                                 }
 331                                                 else
 332                                                 {
 333                                                         user->WriteNumeric(ERR_BANNEDFROMCHAN, chan->name, "Cannot join channel (you're banned)");
 334                                                         user->WriteNumeric(470, chan->name, redir->targetchan, "You are banned from this channel, so you are automatically being transferred to the redirected channel.");
 335                                                         nofollow = true;
 336                                                         Channel::JoinUser(user, redir->targetchan);
 337                                                         nofollow = false;
 338                                                         return MOD_RES_DENY;
 339                                                 }
 340                                         }
 341                                 }
 342                         }
 343                 }
 344                 return MOD_RES_PASSTHRU;
 345         }
 346
 347         Version GetVersion() CXX11_OVERRIDE
 348         {
 349                 return Version("Allows an extended ban (+b) syntax redirecting banned users to another channel", VF_COMMON|VF_VENDOR);
 350         }
 351 };
 352
 353 MODULE_INIT(ModuleBanRedirect)