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 /* $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
  47 class BanRedirect : public ModeWatcher
  48 {
  49         ModeReference ban;
  50  public:
  51         SimpleExtItem<BanRedirectList> extItem;
  52         BanRedirect(Module* parent)
  53                 : ModeWatcher(parent, "ban", MODETYPE_CHANNEL)
  54                 , ban(parent, "ban")
  55                 , extItem("banredirect", parent)
  56         {
  57         }
  58
  59         bool BeforeMode(User* source, User* dest, Channel* channel, std::string &param, bool adding)
  60         {
  61                 /* nick!ident@host -> nick!ident@host
  62                  * nick!ident@host#chan -> nick!ident@host#chan
  63                  * nick@host#chan -> nick!*@host#chan
  64                  * nick!ident#chan -> nick!ident@*#chan
  65                  * nick#chan -> nick!*@*#chan
  66                  */
  67
  68                 if ((channel) && !param.empty())
  69                 {
  70                         BanRedirectList* redirects;
  71
  72                         std::string mask[4];
  73                         enum { NICK, IDENT, HOST, CHAN } current = NICK;
  74                         std::string::iterator start_pos = param.begin();
  75
  76                         if (param.length() >= 2 && param[1] == ':')
  77                                 return true;
  78
  79                         ListModeBase* banlm = static_cast<ListModeBase*>(*ban);
  80                         unsigned int maxbans = banlm->GetLimit(channel);
  81                         ListModeBase::ModeList* list = banlm->GetList(channel);
  82                         if ((list) && (adding) && (maxbans <= list->size()))
  83                         {
  84                                 source->WriteNumeric(478, "%s %s :Channel ban list for %s is full (maximum entries for this channel is %u)", source->nick.c_str(), channel->name.c_str(), 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                         for(int i = 0; i < 3; i++)
 127                         {
 128                                 if(mask[i].empty())
 129                                 {
 130                                         mask[i].assign("*");
 131                                 }
 132                         }
 133
 134                         param.assign(mask[NICK]).append(1, '!').append(mask[IDENT]).append(1, '@').append(mask[HOST]);
 135
 136                         if(mask[CHAN].length())
 137                         {
 138                                 if (adding && IS_LOCAL(source))
 139                                 {
 140                                         if (!ServerInstance->IsChannel(mask[CHAN]))
 141                                         {
 142                                                 source->WriteNumeric(403, "%s %s :Invalid channel name in redirection (%s)", source->nick.c_str(), channel->name.c_str(), mask[CHAN].c_str());
 143                                                 return false;
 144                                         }
 145
 146                                         Channel *c = ServerInstance->FindChan(mask[CHAN]);
 147                                         if (!c)
 148                                         {
 149                                                 source->WriteNumeric(690, "%s :Target channel %s must exist to be set as a redirect.",source->nick.c_str(),mask[CHAN].c_str());
 150                                                 return false;
 151                                         }
 152                                         else if (adding && c->GetPrefixValue(source) < OP_VALUE)
 153                                         {
 154                                                 source->WriteNumeric(690, "%s :You must be opped on %s to set it as a redirect.",source->nick.c_str(), mask[CHAN].c_str());
 155                                                 return false;
 156                                         }
 157
 158                                         if (assign(channel->name) == mask[CHAN])
 159                                         {
 160                                                 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());
 161                                                 return false;
 162                                         }
 163                                 }
 164
 165                                 if(adding)
 166                                 {
 167                                         /* It's a properly valid redirecting ban, and we're adding it */
 168                                         redirects = extItem.get(channel);
 169                                         if (!redirects)
 170                                         {
 171                                                 redirects = new BanRedirectList;
 172                                                 extItem.set(channel, redirects);
 173                                         }
 174
 175                                         /* Here 'param' doesn't have the channel on it yet */
 176                                         redirects->push_back(BanRedirectEntry(mask[CHAN], param));
 177
 178                                         /* Now it does */
 179                                         param.append(mask[CHAN]);
 180                                 }
 181                                 else
 182                                 {
 183                                         /* Removing a ban, if there's no extensible there are no redirecting bans and we're fine. */
 184                                         redirects = extItem.get(channel);
 185                                         if (redirects)
 186                                         {
 187                                                 /* But there were, so we need to remove the matching one if there is one */
 188
 189                                                 for(BanRedirectList::iterator redir = redirects->begin(); redir != redirects->end(); redir++)
 190                                                 {
 191                                                         /* Ugly as fuck */
 192                                                         if((irc::string(redir->targetchan.c_str()) == irc::string(mask[CHAN].c_str())) && (irc::string(redir->banmask.c_str()) == irc::string(param.c_str())))
 193                                                         {
 194                                                                 redirects->erase(redir);
 195
 196                                                                 if(redirects->empty())
 197                                                                 {
 198                                                                         extItem.unset(channel);
 199                                                                 }
 200
 201                                                                 break;
 202                                                         }
 203                                                 }
 204                                         }
 205
 206                                         /* Append the channel so the default +b handler can remove the entry too */
 207                                         param.append(mask[CHAN]);
 208                                 }
 209                         }
 210                 }
 211
 212                 return true;
 213         }
 214 };
 215
 216 class ModuleBanRedirect : public Module
 217 {
 218         BanRedirect re;
 219         bool nofollow;
 220
 221  public:
 222         ModuleBanRedirect()
 223         : re(this)
 224         {
 225                 nofollow = false;
 226         }
 227
 228
 229         void init() CXX11_OVERRIDE
 230         {
 231                 ServerInstance->Modes->AddModeWatcher(&re);
 232                 ServerInstance->Modules->AddService(re.extItem);
 233                 Implementation list[] = { I_OnUserPreJoin };
 234                 ServerInstance->Modules->Attach(list, this, sizeof(list)/sizeof(Implementation));
 235         }
 236
 237         void OnCleanup(int target_type, void* item) CXX11_OVERRIDE
 238         {
 239                 if(target_type == TYPE_CHANNEL)
 240                 {
 241                         Channel* chan = static_cast<Channel*>(item);
 242                         BanRedirectList* redirects = re.extItem.get(chan);
 243
 244                         if(redirects)
 245                         {
 246                                 irc::modestacker modestack(false);
 247
 248                                 for(BanRedirectList::iterator i = redirects->begin(); i != redirects->end(); i++)
 249                                 {
 250                                         modestack.Push('b', i->targetchan.insert(0, i->banmask));
 251                                 }
 252
 253                                 for(BanRedirectList::iterator i = redirects->begin(); i != redirects->end(); i++)
 254                                 {
 255                                         modestack.PushPlus();
 256                                         modestack.Push('b', i->banmask);
 257                                 }
 258
 259                                 std::vector<std::string> stackresult;
 260                                 stackresult.push_back(chan->name);
 261                                 while (modestack.GetStackedLine(stackresult))
 262                                 {
 263                                         ServerInstance->Modes->Process(stackresult, ServerInstance->FakeClient);
 264                                         stackresult.erase(stackresult.begin() + 1, stackresult.end());
 265                                 }
 266                         }
 267                 }
 268         }
 269
 270         ModResult OnUserPreJoin(LocalUser* user, Channel* chan, const std::string& cname, std::string& privs, const std::string& keygiven) CXX11_OVERRIDE
 271         {
 272                 if (chan)
 273                 {
 274                         BanRedirectList* redirects = re.extItem.get(chan);
 275
 276                         if (redirects)
 277                         {
 278                                 /* We actually had some ban redirects to check */
 279
 280                                 /* This was replaced with user->MakeHostIP() when I had a snprintf(), but MakeHostIP() doesn't seem to add the nick.
 281                                  * Maybe we should have a GetFullIPHost() or something to match GetFullHost() and GetFullRealHost?
 282                                  */
 283
 284                                 ModResult result;
 285                                 FIRST_MOD_RESULT(OnCheckChannelBan, result, (user, chan));
 286                                 if (result == MOD_RES_ALLOW)
 287                                 {
 288                                         // they have a ban exception
 289                                         return MOD_RES_PASSTHRU;
 290                                 }
 291
 292                                 std::string ipmask(user->nick);
 293                                 ipmask.append(1, '!').append(user->MakeHostIP());
 294
 295                                 for(BanRedirectList::iterator redir = redirects->begin(); redir != redirects->end(); redir++)
 296                                 {
 297                                         if(InspIRCd::Match(user->GetFullRealHost(), redir->banmask) || InspIRCd::Match(user->GetFullHost(), redir->banmask) || InspIRCd::MatchCIDR(ipmask, redir->banmask))
 298                                         {
 299                                                 /* This prevents recursion when a user sets multiple ban redirects in a chain
 300                                                  * (thanks Potter)
 301                                                  *
 302                                                  * If we're here and nofollow is true then we're already redirecting this user
 303                                                  * and there's a redirecting ban set on this channel that matches him, too.
 304                                                  * Deny both joins.
 305                                                  */
 306                                                 if (nofollow)
 307                                                         return MOD_RES_DENY;
 308
 309                                                 /* tell them they're banned and are being transferred */
 310                                                 Channel* destchan = ServerInstance->FindChan(redir->targetchan);
 311                                                 std::string destlimit;
 312
 313                                                 if (destchan)
 314                                                         destlimit = destchan->GetModeParameter('l');
 315
 316                                                 if(destchan && ServerInstance->Modules->Find("m_redirect.so") && destchan->IsModeSet('L') && !destlimit.empty() && (destchan->GetUserCounter() >= atoi(destlimit.c_str())))
 317                                                 {
 318                                                         user->WriteNumeric(474, "%s %s :Cannot join channel (You are banned)", user->nick.c_str(), chan->name.c_str());
 319                                                         return MOD_RES_DENY;
 320                                                 }
 321                                                 else
 322                                                 {
 323                                                         user->WriteNumeric(474, "%s %s :Cannot join channel (You are banned)", user->nick.c_str(), chan->name.c_str());
 324                                                         user->WriteNumeric(470, "%s %s %s :You are banned from this channel, so you are automatically transfered to the redirected channel.", user->nick.c_str(), chan->name.c_str(), redir->targetchan.c_str());
 325                                                         nofollow = true;
 326                                                         Channel::JoinUser(user, redir->targetchan);
 327                                                         nofollow = false;
 328                                                         return MOD_RES_DENY;
 329                                                 }
 330                                         }
 331                                 }
 332                         }
 333                 }
 334                 return MOD_RES_PASSTHRU;
 335         }
 336
 337         ~ModuleBanRedirect()
 338         {
 339                 /* XXX is this the best place to do this? */
 340                 if (!ServerInstance->Modes->DelModeWatcher(&re))
 341                         ServerInstance->Logs->Log("m_banredirect.so", LOG_DEBUG, "Failed to delete modewatcher!");
 342         }
 343
 344         Version GetVersion() CXX11_OVERRIDE
 345         {
 346                 return Version("Allows an extended ban (+b) syntax redirecting banned users to another channel", VF_COMMON|VF_VENDOR);
 347         }
 348 };
 349
 350 MODULE_INIT(ModuleBanRedirect)