src/modules/m_banredirect.cpp

   1 /*
   2  * InspIRCd -- Internet Relay Chat Daemon
   3  *
   4  *   Copyright (C) 2018 linuxdaemon <linuxdaemon.irc@gmail.com>
   5  *   Copyright (C) 2014 Adam <Adam@anope.org>
   6  *   Copyright (C) 2013-2016 Attila Molnar <attilamolnar@hush.com>
   7  *   Copyright (C) 2013, 2017-2018 Sadie Powell <sadie@witchery.services>
   8  *   Copyright (C) 2013 Daniel Vassdal <shutter@canternet.org>
   9  *   Copyright (C) 2012, 2019 Robby <robby@chatbelgie.be>
  10  *   Copyright (C) 2009-2010 Daniel De Graaf <danieldg@inspircd.org>
  11  *   Copyright (C) 2009 Matt Smith <dz@inspircd.org>
  12  *   Copyright (C) 2008, 2010 Craig Edwards <brain@inspircd.org>
  13  *   Copyright (C) 2008 Uli Schlachter <psychon@inspircd.org>
  14  *   Copyright (C) 2007-2009 Robin Burchell <robin+git@viroteck.net>
  15  *   Copyright (C) 2007 Oliver Lupton <om@inspircd.org>
  16  *   Copyright (C) 2007 Dennis Friis <peavey@inspircd.org>
  17  *
  18  * This file is part of InspIRCd.  InspIRCd is free software: you can
  19  * redistribute it and/or modify it under the terms of the GNU General Public
  20  * License as published by the Free Software Foundation, version 2.
  21  *
  22  * This program is distributed in the hope that it will be useful, but WITHOUT
  23  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  24  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  25  * details.
  26  *
  27  * You should have received a copy of the GNU General Public License
  28  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  29  */
  30
  31
  32 #include "inspircd.h"
  33 #include "listmode.h"
  34
  35 /* Originally written by Om, January 2009
  36  */
  37
  38 class BanRedirectEntry
  39 {
  40  public:
  41         std::string targetchan;
  42         std::string banmask;
  43
  44         BanRedirectEntry(const std::string &target = "", const std::string &mask = "")
  45         : targetchan(target), banmask(mask)
  46         {
  47         }
  48 };
  49
  50 typedef std::vector<BanRedirectEntry> BanRedirectList;
  51
  52 class BanRedirect : public ModeWatcher
  53 {
  54         ChanModeReference ban;
  55  public:
  56         SimpleExtItem<BanRedirectList> extItem;
  57         BanRedirect(Module* parent)
  58                 : ModeWatcher(parent, "ban", MODETYPE_CHANNEL)
  59                 , ban(parent, "ban")
  60                 , extItem("banredirect", ExtensionItem::EXT_CHANNEL, parent)
  61         {
  62         }
  63
  64         bool BeforeMode(User* source, User* dest, Channel* channel, std::string& param, bool adding) CXX11_OVERRIDE
  65         {
  66                 /* nick!ident@host -> nick!ident@host
  67                  * nick!ident@host#chan -> nick!ident@host#chan
  68                  * nick@host#chan -> nick!*@host#chan
  69                  * nick!ident#chan -> nick!ident@*#chan
  70                  * nick#chan -> nick!*@*#chan
  71                  */
  72
  73                 if ((channel) && !param.empty())
  74                 {
  75                         BanRedirectList* redirects;
  76
  77                         std::string mask[4];
  78                         enum { NICK, IDENT, HOST, CHAN } current = NICK;
  79                         std::string::iterator start_pos = param.begin();
  80
  81                         if (param.length() >= 2 && param[1] == ':')
  82                                 return true;
  83
  84                         if (param.find('#') == std::string::npos)
  85                                 return true;
  86
  87                         ListModeBase* banlm = static_cast<ListModeBase*>(*ban);
  88                         unsigned int maxbans = banlm->GetLimit(channel);
  89                         ListModeBase::ModeList* list = banlm->GetList(channel);
  90                         if ((list) && (adding) && (maxbans <= list->size()))
  91                         {
  92                                 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));
  93                                 return false;
  94                         }
  95
  96                         for(std::string::iterator curr = start_pos; curr != param.end(); curr++)
  97                         {
  98                                 switch(*curr)
  99                                 {
 100                                         case '!':
 101                                                 if (current != NICK)
 102                                                         break;
 103                                                 mask[current].assign(start_pos, curr);
 104                                                 current = IDENT;
 105                                                 start_pos = curr+1;
 106                                                 break;
 107                                         case '@':
 108                                                 if (current != IDENT)
 109                                                         break;
 110                                                 mask[current].assign(start_pos, curr);
 111                                                 current = HOST;
 112                                                 start_pos = curr+1;
 113                                                 break;
 114                                         case '#':
 115                                                 if (current == CHAN)
 116                                                         break;
 117                                                 mask[current].assign(start_pos, curr);
 118                                                 current = CHAN;
 119                                                 start_pos = curr;
 120                                                 break;
 121                                 }
 122                         }
 123
 124                         if(mask[current].empty())
 125                         {
 126                                 mask[current].assign(start_pos, param.end());
 127                         }
 128
 129                         /* nick@host wants to be changed to *!nick@host rather than nick!*@host... */
 130                         if(mask[NICK].length() && mask[HOST].length() && mask[IDENT].empty())
 131                         {
 132                                 /* std::string::swap() is fast - it runs in constant time */
 133                                 mask[NICK].swap(mask[IDENT]);
 134                         }
 135
 136                         if (!mask[NICK].empty() && mask[IDENT].empty() && mask[HOST].empty())
 137                         {
 138                                 if (mask[NICK].find('.') != std::string::npos || mask[NICK].find(':') != std::string::npos)
 139                                 {
 140                                         mask[NICK].swap(mask[HOST]);
 141                                 }
 142                         }
 143
 144                         for(int i = 0; i < 3; i++)
 145                         {
 146                                 if(mask[i].empty())
 147                                 {
 148                                         mask[i].assign("*");
 149                                 }
 150                         }
 151
 152                         param.assign(mask[NICK]).append(1, '!').append(mask[IDENT]).append(1, '@').append(mask[HOST]);
 153
 154                         if(mask[CHAN].length())
 155                         {
 156                                 if (adding && IS_LOCAL(source))
 157                                 {
 158                                         if (!ServerInstance->IsChannel(mask[CHAN]))
 159                                         {
 160                                                 source->WriteNumeric(ERR_NOSUCHCHANNEL, channel->name, InspIRCd::Format("Invalid channel name in redirection (%s)", mask[CHAN].c_str()));
 161                                                 return false;
 162                                         }
 163
 164                                         Channel *c = ServerInstance->FindChan(mask[CHAN]);
 165                                         if (!c)
 166                                         {
 167                                                 source->WriteNumeric(690, InspIRCd::Format("Target channel %s must exist to be set as a redirect.", mask[CHAN].c_str()));
 168                                                 return false;
 169                                         }
 170                                         else if (adding && c->GetPrefixValue(source) < OP_VALUE)
 171                                         {
 172                                                 source->WriteNumeric(690, InspIRCd::Format("You must be opped on %s to set it as a redirect.", mask[CHAN].c_str()));
 173                                                 return false;
 174                                         }
 175
 176                                         if (irc::equals(channel->name, mask[CHAN]))
 177                                         {
 178                                                 source->WriteNumeric(690, channel->name, "You cannot set a ban redirection to the channel the ban is on");
 179                                                 return false;
 180                                         }
 181                                 }
 182
 183                                 if(adding)
 184                                 {
 185                                         /* It's a properly valid redirecting ban, and we're adding it */
 186                                         redirects = extItem.get(channel);
 187                                         if (!redirects)
 188                                         {
 189                                                 redirects = new BanRedirectList;
 190                                                 extItem.set(channel, redirects);
 191                                         }
 192                                         else
 193                                         {
 194                                                 for (BanRedirectList::iterator redir = redirects->begin(); redir != redirects->end(); ++redir)
 195                                                 {
 196                                                         // Mimic the functionality used when removing the mode
 197                                                         if (irc::equals(redir->targetchan, mask[CHAN]) && irc::equals(redir->banmask, param))
 198                                                         {
 199                                                                 // Make sure the +b handler will still set the right ban
 200                                                                 param.append(mask[CHAN]);
 201                                                                 // Silently ignore the duplicate and don't set metadata
 202                                                                 // This still allows channel ops to set/unset a redirect ban to clear "ghost" redirects
 203                                                                 return true;
 204                                                         }
 205                                                 }
 206                                         }
 207
 208                                         /* Here 'param' doesn't have the channel on it yet */
 209                                         redirects->push_back(BanRedirectEntry(mask[CHAN], param));
 210
 211                                         /* Now it does */
 212                                         param.append(mask[CHAN]);
 213                                 }
 214                                 else
 215                                 {
 216                                         /* Removing a ban, if there's no extensible there are no redirecting bans and we're fine. */
 217                                         redirects = extItem.get(channel);
 218                                         if (redirects)
 219                                         {
 220                                                 /* But there were, so we need to remove the matching one if there is one */
 221
 222                                                 for(BanRedirectList::iterator redir = redirects->begin(); redir != redirects->end(); redir++)
 223                                                 {
 224                                                         if ((irc::equals(redir->targetchan, mask[CHAN])) && (irc::equals(redir->banmask, param)))
 225                                                         {
 226                                                                 redirects->erase(redir);
 227
 228                                                                 if(redirects->empty())
 229                                                                 {
 230                                                                         extItem.unset(channel);
 231                                                                 }
 232
 233                                                                 break;
 234                                                         }
 235                                                 }
 236                                         }
 237
 238                                         /* Append the channel so the default +b handler can remove the entry too */
 239                                         param.append(mask[CHAN]);
 240                                 }
 241                         }
 242                 }
 243
 244                 return true;
 245         }
 246 };
 247
 248 class ModuleBanRedirect : public Module
 249 {
 250         BanRedirect re;
 251         bool nofollow;
 252         ChanModeReference limitmode;
 253         ChanModeReference redirectmode;
 254
 255  public:
 256         ModuleBanRedirect()
 257                 : re(this)
 258                 , nofollow(false)
 259                 , limitmode(this, "limit")
 260                 , redirectmode(this, "redirect")
 261         {
 262         }
 263
 264         void OnCleanup(ExtensionItem::ExtensibleType type, Extensible* item) CXX11_OVERRIDE
 265         {
 266                 if (type == ExtensionItem::EXT_CHANNEL)
 267                 {
 268                         Channel* chan = static_cast<Channel*>(item);
 269                         BanRedirectList* redirects = re.extItem.get(chan);
 270
 271                         if(redirects)
 272                         {
 273                                 ModeHandler* ban = ServerInstance->Modes->FindMode('b', MODETYPE_CHANNEL);
 274                                 Modes::ChangeList changelist;
 275
 276                                 for(BanRedirectList::iterator i = redirects->begin(); i != redirects->end(); i++)
 277                                         changelist.push_remove(ban, i->targetchan.insert(0, i->banmask));
 278
 279                                 for(BanRedirectList::iterator i = redirects->begin(); i != redirects->end(); i++)
 280                                         changelist.push_add(ban, i->banmask);
 281
 282                                 ServerInstance->Modes->Process(ServerInstance->FakeClient, chan, NULL, changelist, ModeParser::MODE_LOCALONLY);
 283                         }
 284                 }
 285         }
 286
 287         ModResult OnUserPreJoin(LocalUser* user, Channel* chan, const std::string& cname, std::string& privs, const std::string& keygiven) CXX11_OVERRIDE
 288         {
 289                 if (chan)
 290                 {
 291                         BanRedirectList* redirects = re.extItem.get(chan);
 292
 293                         if (redirects)
 294                         {
 295                                 /* We actually had some ban redirects to check */
 296
 297                                 /* This was replaced with user->MakeHostIP() when I had a snprintf(), but MakeHostIP() doesn't seem to add the nick.
 298                                  * Maybe we should have a GetFullIPHost() or something to match GetFullHost() and GetFullRealHost?
 299                                  */
 300
 301                                 ModResult result;
 302                                 FIRST_MOD_RESULT(OnCheckChannelBan, result, (user, chan));
 303                                 if (result == MOD_RES_ALLOW)
 304                                 {
 305                                         // they have a ban exception
 306                                         return MOD_RES_PASSTHRU;
 307                                 }
 308
 309                                 std::string ipmask(user->nick);
 310                                 ipmask.append(1, '!').append(user->MakeHostIP());
 311
 312                                 for(BanRedirectList::iterator redir = redirects->begin(); redir != redirects->end(); redir++)
 313                                 {
 314                                         if(InspIRCd::Match(user->GetFullRealHost(), redir->banmask) || InspIRCd::Match(user->GetFullHost(), redir->banmask) || InspIRCd::MatchCIDR(ipmask, redir->banmask))
 315                                         {
 316                                                 /* This prevents recursion when a user sets multiple ban redirects in a chain
 317                                                  * (thanks Potter)
 318                                                  *
 319                                                  * If we're here and nofollow is true then we're already redirecting this user
 320                                                  * and there's a redirecting ban set on this channel that matches him, too.
 321                                                  * Deny both joins.
 322                                                  */
 323                                                 if (nofollow)
 324                                                         return MOD_RES_DENY;
 325
 326                                                 /* tell them they're banned and are being transferred */
 327                                                 Channel* destchan = ServerInstance->FindChan(redir->targetchan);
 328                                                 std::string destlimit;
 329
 330                                                 if (destchan)
 331                                                         destlimit = destchan->GetModeParameter(limitmode);
 332
 333                                                 if(destchan && destchan->IsModeSet(redirectmode) && !destlimit.empty() && (destchan->GetUserCounter() >= ConvToNum<size_t>(destlimit)))
 334                                                 {
 335                                                         user->WriteNumeric(ERR_BANNEDFROMCHAN, chan->name, "Cannot join channel (you're banned)");
 336                                                         return MOD_RES_DENY;
 337                                                 }
 338                                                 else
 339                                                 {
 340                                                         user->WriteNumeric(ERR_BANNEDFROMCHAN, chan->name, "Cannot join channel (you're banned)");
 341                                                         user->WriteNumeric(470, chan->name, redir->targetchan, "You are banned from this channel, so you are automatically being transferred to the redirected channel.");
 342                                                         nofollow = true;
 343                                                         Channel::JoinUser(user, redir->targetchan);
 344                                                         nofollow = false;
 345                                                         return MOD_RES_DENY;
 346                                                 }
 347                                         }
 348                                 }
 349                         }
 350                 }
 351                 return MOD_RES_PASSTHRU;
 352         }
 353
 354         Version GetVersion() CXX11_OVERRIDE
 355         {
 356                 return Version("Allows specifying a channel to redirect a banned user to in the ban mask.", VF_COMMON|VF_VENDOR);
 357         }
 358 };
 359
 360 MODULE_INIT(ModuleBanRedirect)