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(adding && (channel->bans.size() > static_cast<unsigned>(maxbans)))
  79                         {
  80                                 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);
  81                                 return false;
  82                         }
  83
  84                         for(std::string::iterator curr = start_pos; curr != param.end(); curr++)
  85                         {
  86                                 switch(*curr)
  87                                 {
  88                                         case '!':
  89                                                 mask[current].assign(start_pos, curr);
  90                                                 current = IDENT;
  91                                                 start_pos = curr+1;
  92                                                 break;
  93                                         case '@':
  94                                                 mask[current].assign(start_pos, curr);
  95                                                 current = HOST;
  96                                                 start_pos = curr+1;
  97                                                 break;
  98                                         case '#':
  99                                                 /* bug #921: don't barf when redirecting to ## channels */
 100                                                 if (current != CHAN)
 101                                                 {
 102                                                         mask[current].assign(start_pos, curr);
 103                                                         current = CHAN;
 104                                                         start_pos = curr;
 105                                                 }
 106                                                 break;
 107                                 }
 108                         }
 109
 110                         if(mask[current].empty())
 111                         {
 112                                 mask[current].assign(start_pos, param.end());
 113                         }
 114
 115                         /* nick@host wants to be changed to *!nick@host rather than nick!*@host... */
 116                         if(mask[NICK].length() && mask[HOST].length() && mask[IDENT].empty())
 117                         {
 118                                 /* std::string::swap() is fast - it runs in constant time */
 119                                 mask[NICK].swap(mask[IDENT]);
 120                         }
 121
 122                         for(int i = 0; i < 3; i++)
 123                         {
 124                                 if(mask[i].empty())
 125                                 {
 126                                         mask[i].assign("*");
 127                                 }
 128                         }
 129
 130                         param.assign(mask[NICK]).append(1, '!').append(mask[IDENT]).append(1, '@').append(mask[HOST]);
 131
 132                         if(mask[CHAN].length())
 133                         {
 134                                 if (adding && IS_LOCAL(source))
 135                                 {
 136                                         if (!ServerInstance->IsChannel(mask[CHAN].c_str(),  ServerInstance->Config->Limits.ChanMax))
 137                                         {
 138                                                 source->WriteNumeric(403, "%s %s :Invalid channel name in redirection (%s)", source->nick.c_str(), channel->name.c_str(), mask[CHAN].c_str());
 139                                                 return false;
 140                                         }
 141
 142                                         Channel *c = ServerInstance->FindChan(mask[CHAN]);
 143                                         if (!c)
 144                                         {
 145                                                 source->WriteNumeric(690, "%s :Target channel %s must exist to be set as a redirect.",source->nick.c_str(),mask[CHAN].c_str());
 146                                                 return false;
 147                                         }
 148                                         else if (adding && c->GetPrefixValue(source) < OP_VALUE)
 149                                         {
 150                                                 source->WriteNumeric(690, "%s :You must be opped on %s to set it as a redirect.",source->nick.c_str(), mask[CHAN].c_str());
 151                                                 return false;
 152                                         }
 153
 154                                         if (assign(channel->name) == mask[CHAN])
 155                                         {
 156                                                 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());
 157                                                 return false;
 158                                         }
 159                                 }
 160
 161                                 if(adding)
 162                                 {
 163                                         /* It's a properly valid redirecting ban, and we're adding it */
 164                                         redirects = extItem.get(channel);
 165                                         if (!redirects)
 166                                         {
 167                                                 redirects = new BanRedirectList;
 168                                                 extItem.set(channel, redirects);
 169                                         }
 170
 171                                         /* Here 'param' doesn't have the channel on it yet */
 172                                         redirects->push_back(BanRedirectEntry(mask[CHAN], param));
 173
 174                                         /* Now it does */
 175                                         param.append(mask[CHAN]);
 176                                 }
 177                                 else
 178                                 {
 179                                         /* Removing a ban, if there's no extensible there are no redirecting bans and we're fine. */
 180                                         redirects = extItem.get(channel);
 181                                         if (redirects)
 182                                         {
 183                                                 /* But there were, so we need to remove the matching one if there is one */
 184
 185                                                 for(BanRedirectList::iterator redir = redirects->begin(); redir != redirects->end(); redir++)
 186                                                 {
 187                                                         /* Ugly as fuck */
 188                                                         if((irc::string(redir->targetchan.c_str()) == irc::string(mask[CHAN].c_str())) && (irc::string(redir->banmask.c_str()) == irc::string(param.c_str())))
 189                                                         {
 190                                                                 redirects->erase(redir);
 191
 192                                                                 if(redirects->empty())
 193                                                                 {
 194                                                                         extItem.unset(channel);
 195                                                                 }
 196
 197                                                                 break;
 198                                                         }
 199                                                 }
 200                                         }
 201
 202                                         /* Append the channel so the default +b handler can remove the entry too */
 203                                         param.append(mask[CHAN]);
 204                                 }
 205                         }
 206                 }
 207
 208                 return true;
 209         }
 210 };
 211
 212 class ModuleBanRedirect : public Module
 213 {
 214         BanRedirect re;
 215         bool nofollow;
 216
 217  public:
 218         ModuleBanRedirect()
 219         : re(this)
 220         {
 221                 nofollow = false;
 222         }
 223
 224
 225         void init()
 226         {
 227                 if(!ServerInstance->Modes->AddModeWatcher(&re))
 228                         throw ModuleException("Could not add mode watcher");
 229
 230                 ServerInstance->Modules->AddService(re.extItem);
 231                 Implementation list[] = { I_OnUserPreJoin };
 232                 ServerInstance->Modules->Attach(list, this, sizeof(list)/sizeof(Implementation));
 233         }
 234
 235         virtual void OnCleanup(int target_type, void* item)
 236         {
 237                 if(target_type == TYPE_CHANNEL)
 238                 {
 239                         Channel* chan = static_cast<Channel*>(item);
 240                         BanRedirectList* redirects = re.extItem.get(chan);
 241
 242                         if(redirects)
 243                         {
 244                                 irc::modestacker modestack(false);
 245                                 StringDeque stackresult;
 246                                 std::vector<std::string> mode_junk;
 247                                 mode_junk.push_back(chan->name);
 248
 249                                 for(BanRedirectList::iterator i = redirects->begin(); i != redirects->end(); i++)
 250                                 {
 251                                         modestack.Push('b', i->targetchan.insert(0, i->banmask));
 252                                 }
 253
 254                                 for(BanRedirectList::iterator i = redirects->begin(); i != redirects->end(); i++)
 255                                 {
 256                                         modestack.PushPlus();
 257                                         modestack.Push('b', i->banmask);
 258                                 }
 259
 260                                 while(modestack.GetStackedLine(stackresult))
 261                                 {
 262                                         mode_junk.insert(mode_junk.end(), stackresult.begin(), stackresult.end());
 263                                         ServerInstance->SendMode(mode_junk, ServerInstance->FakeClient);
 264                                         mode_junk.erase(mode_junk.begin() + 1, mode_junk.end());
 265                                 }
 266                         }
 267                 }
 268         }
 269
 270         virtual ModResult OnUserPreJoin(User* user, Channel* chan, const char* cname, std::string &privs, const std::string &keygiven)
 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 transferred 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.c_str(), false, "", false, ServerInstance->Time());
 327                                                         nofollow = false;
 328                                                         return MOD_RES_DENY;
 329                                                 }
 330                                         }
 331                                 }
 332                         }
 333                 }
 334                 return MOD_RES_PASSTHRU;
 335         }
 336
 337         virtual ~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", DEBUG, "Failed to delete modewatcher!");
 342         }
 343
 344         virtual Version GetVersion()
 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)