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         bool operator<(const BanRedirectEntry& other) const
  45         {
  46                 if (targetchan != other.targetchan)
  47                         return targetchan < other.targetchan;
  48
  49                 return banmask < other.banmask;
  50         }
  51 };
  52
  53 typedef std::set<BanRedirectEntry> BanRedirectList;
  54 typedef std::deque<std::string> StringDeque;
  55
  56 class BanRedirect : public ModeWatcher
  57 {
  58  public:
  59         SimpleExtItem<BanRedirectList> extItem;
  60         BanRedirect(Module* parent) : ModeWatcher(parent, 'b', MODETYPE_CHANNEL),
  61                 extItem("banredirect", parent)
  62         {
  63         }
  64
  65         bool BeforeMode(User* source, User* dest, Channel* channel, std::string &param, bool adding, ModeType type)
  66         {
  67                 /* nick!ident@host -> nick!ident@host
  68                  * nick!ident@host#chan -> nick!ident@host#chan
  69                  * nick@host#chan -> nick!*@host#chan
  70                  * nick!ident#chan -> nick!ident@*#chan
  71                  * nick#chan -> nick!*@*#chan
  72                  */
  73
  74                 if(channel && (type == MODETYPE_CHANNEL) && param.length())
  75                 {
  76                         BanRedirectList* redirects;
  77
  78                         std::string mask[4];
  79                         enum { NICK, IDENT, HOST, CHAN } current = NICK;
  80                         std::string::iterator start_pos = param.begin();
  81                         long maxbans = channel->GetMaxBans();
  82
  83                         if (param.length() >= 2 && param[1] == ':')
  84                                 return true;
  85
  86                         if (param.find('#') == std::string::npos)
  87                                 return true;
  88
  89                         if(adding && (channel->bans.size() > static_cast<unsigned>(maxbans)))
  90                         {
  91                                 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);
  92                                 return false;
  93                         }
  94
  95                         for(std::string::iterator curr = start_pos; curr != param.end(); curr++)
  96                         {
  97                                 switch(*curr)
  98                                 {
  99                                         case '!':
 100                                                 mask[current].assign(start_pos, curr);
 101                                                 current = IDENT;
 102                                                 start_pos = curr+1;
 103                                                 break;
 104                                         case '@':
 105                                                 mask[current].assign(start_pos, curr);
 106                                                 current = HOST;
 107                                                 start_pos = curr+1;
 108                                                 break;
 109                                         case '#':
 110                                                 /* bug #921: don't barf when redirecting to ## channels */
 111                                                 if (current != CHAN)
 112                                                 {
 113                                                         mask[current].assign(start_pos, curr);
 114                                                         current = CHAN;
 115                                                         start_pos = curr;
 116                                                 }
 117                                                 break;
 118                                 }
 119                         }
 120
 121                         if(mask[current].empty())
 122                         {
 123                                 mask[current].assign(start_pos, param.end());
 124                         }
 125
 126                         /* nick@host wants to be changed to *!nick@host rather than nick!*@host... */
 127                         if(mask[NICK].length() && mask[HOST].length() && mask[IDENT].empty())
 128                         {
 129                                 /* std::string::swap() is fast - it runs in constant time */
 130                                 mask[NICK].swap(mask[IDENT]);
 131                         }
 132
 133                         if (!mask[NICK].empty() && mask[IDENT].empty() && mask[HOST].empty())
 134                         {
 135                                 if (mask[NICK].find('.') != std::string::npos || mask[NICK].find(':') != std::string::npos)
 136                                 {
 137                                         mask[NICK].swap(mask[HOST]);
 138                                 }
 139                         }
 140
 141                         for(int i = 0; i < 3; i++)
 142                         {
 143                                 if(mask[i].empty())
 144                                 {
 145                                         mask[i].assign("*");
 146                                 }
 147                         }
 148
 149                         param.assign(mask[NICK]).append(1, '!').append(mask[IDENT]).append(1, '@').append(mask[HOST]);
 150
 151                         if(mask[CHAN].length())
 152                         {
 153                                 if (adding && IS_LOCAL(source))
 154                                 {
 155                                         if (!ServerInstance->IsChannel(mask[CHAN].c_str(),  ServerInstance->Config->Limits.ChanMax))
 156                                         {
 157                                                 source->WriteNumeric(403, "%s %s :Invalid channel name in redirection (%s)", source->nick.c_str(), channel->name.c_str(), mask[CHAN].c_str());
 158                                                 return false;
 159                                         }
 160
 161                                         Channel *c = ServerInstance->FindChan(mask[CHAN]);
 162                                         if (!c)
 163                                         {
 164                                                 source->WriteNumeric(690, "%s :Target channel %s must exist to be set as a redirect.",source->nick.c_str(),mask[CHAN].c_str());
 165                                                 return false;
 166                                         }
 167                                         else if (adding && c->GetPrefixValue(source) < OP_VALUE)
 168                                         {
 169                                                 source->WriteNumeric(690, "%s :You must be opped on %s to set it as a redirect.",source->nick.c_str(), mask[CHAN].c_str());
 170                                                 return false;
 171                                         }
 172
 173                                         if (assign(channel->name) == mask[CHAN])
 174                                         {
 175                                                 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());
 176                                                 return false;
 177                                         }
 178                                 }
 179
 180                                 if(adding)
 181                                 {
 182                                         /* It's a properly valid redirecting ban, and we're adding it */
 183                                         redirects = extItem.get(channel);
 184                                         if (!redirects)
 185                                         {
 186                                                 redirects = new BanRedirectList;
 187                                                 extItem.set(channel, redirects);
 188                                         }
 189
 190                                         /* Here 'param' doesn't have the channel on it yet */
 191                                         redirects->insert(BanRedirectEntry(mask[CHAN], param));
 192
 193                                         /* Now it does */
 194                                         param.append(mask[CHAN]);
 195                                 }
 196                                 else
 197                                 {
 198                                         /* Removing a ban, if there's no extensible there are no redirecting bans and we're fine. */
 199                                         redirects = extItem.get(channel);
 200                                         if (redirects)
 201                                         {
 202                                                 /* But there were, so we need to remove the matching one if there is one */
 203
 204                                                 for(BanRedirectList::iterator redir = redirects->begin(); redir != redirects->end(); redir++)
 205                                                 {
 206                                                         /* Ugly as fuck */
 207                                                         if((irc::string(redir->targetchan.c_str()) == irc::string(mask[CHAN].c_str())) && (irc::string(redir->banmask.c_str()) == irc::string(param.c_str())))
 208                                                         {
 209                                                                 redirects->erase(redir);
 210
 211                                                                 if(redirects->empty())
 212                                                                 {
 213                                                                         extItem.unset(channel);
 214                                                                 }
 215
 216                                                                 break;
 217                                                         }
 218                                                 }
 219                                         }
 220
 221                                         /* Append the channel so the default +b handler can remove the entry too */
 222                                         param.append(mask[CHAN]);
 223                                 }
 224                         }
 225                 }
 226
 227                 return true;
 228         }
 229 };
 230
 231 class ModuleBanRedirect : public Module
 232 {
 233         BanRedirect re;
 234         bool nofollow;
 235
 236  public:
 237         ModuleBanRedirect()
 238         : re(this)
 239         {
 240                 nofollow = false;
 241         }
 242
 243
 244         void init()
 245         {
 246                 if(!ServerInstance->Modes->AddModeWatcher(&re))
 247                         throw ModuleException("Could not add mode watcher");
 248
 249                 ServerInstance->Modules->AddService(re.extItem);
 250                 Implementation list[] = { I_OnUserPreJoin };
 251                 ServerInstance->Modules->Attach(list, this, sizeof(list)/sizeof(Implementation));
 252         }
 253
 254         virtual void OnCleanup(int target_type, void* item)
 255         {
 256                 if(target_type == TYPE_CHANNEL)
 257                 {
 258                         Channel* chan = static_cast<Channel*>(item);
 259                         BanRedirectList* redirects = re.extItem.get(chan);
 260
 261                         if(redirects)
 262                         {
 263                                 irc::modestacker modestack(false);
 264                                 StringDeque stackresult;
 265                                 std::vector<std::string> mode_junk;
 266                                 mode_junk.push_back(chan->name);
 267
 268                                 for(BanRedirectList::iterator i = redirects->begin(); i != redirects->end(); i++)
 269                                 {
 270                                         modestack.Push('b', i->banmask + i->targetchan);
 271                                 }
 272
 273                                 for(BanRedirectList::iterator i = redirects->begin(); i != redirects->end(); i++)
 274                                 {
 275                                         modestack.PushPlus();
 276                                         modestack.Push('b', i->banmask);
 277                                 }
 278
 279                                 while(modestack.GetStackedLine(stackresult))
 280                                 {
 281                                         mode_junk.insert(mode_junk.end(), stackresult.begin(), stackresult.end());
 282                                         ServerInstance->SendMode(mode_junk, ServerInstance->FakeClient);
 283                                         mode_junk.erase(mode_junk.begin() + 1, mode_junk.end());
 284                                 }
 285                         }
 286                 }
 287         }
 288
 289         virtual ModResult OnUserPreJoin(User* user, Channel* chan, const char* cname, std::string &privs, const std::string &keygiven)
 290         {
 291                 if (chan)
 292                 {
 293                         BanRedirectList* redirects = re.extItem.get(chan);
 294
 295                         if (redirects)
 296                         {
 297                                 /* We actually had some ban redirects to check */
 298
 299                                 /* This was replaced with user->MakeHostIP() when I had a snprintf(), but MakeHostIP() doesn't seem to add the nick.
 300                                  * Maybe we should have a GetFullIPHost() or something to match GetFullHost() and GetFullRealHost?
 301                                  */
 302
 303                                 ModResult result;
 304                                 FIRST_MOD_RESULT(OnCheckChannelBan, result, (user, chan));
 305                                 if (result == MOD_RES_ALLOW)
 306                                 {
 307                                         // they have a ban exception
 308                                         return MOD_RES_PASSTHRU;
 309                                 }
 310
 311                                 std::string ipmask(user->nick);
 312                                 ipmask.append(1, '!').append(user->MakeHostIP());
 313
 314                                 for(BanRedirectList::iterator redir = redirects->begin(); redir != redirects->end(); redir++)
 315                                 {
 316                                         if(InspIRCd::Match(user->GetFullRealHost(), redir->banmask) || InspIRCd::Match(user->GetFullHost(), redir->banmask) || InspIRCd::MatchCIDR(ipmask, redir->banmask))
 317                                         {
 318                                                 /* This prevents recursion when a user sets multiple ban redirects in a chain
 319                                                  * (thanks Potter)
 320                                                  *
 321                                                  * If we're here and nofollow is true then we're already redirecting this user
 322                                                  * and there's a redirecting ban set on this channel that matches him, too.
 323                                                  * Deny both joins.
 324                                                  */
 325                                                 if (nofollow)
 326                                                         return MOD_RES_DENY;
 327
 328                                                 /* tell them they're banned and are being transferred */
 329                                                 Channel* destchan = ServerInstance->FindChan(redir->targetchan);
 330                                                 std::string destlimit;
 331
 332                                                 if (destchan)
 333                                                         destlimit = destchan->GetModeParameter('l');
 334
 335                                                 if(destchan && ServerInstance->Modules->Find("m_redirect.so") && destchan->IsModeSet('L') && !destlimit.empty() && (destchan->GetUserCounter() >= atoi(destlimit.c_str())))
 336                                                 {
 337                                                         user->WriteNumeric(474, "%s %s :Cannot join channel (You are banned)", user->nick.c_str(), chan->name.c_str());
 338                                                         return MOD_RES_DENY;
 339                                                 }
 340                                                 else
 341                                                 {
 342                                                         user->WriteNumeric(474, "%s %s :Cannot join channel (You are banned)", user->nick.c_str(), chan->name.c_str());
 343                                                         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());
 344                                                         nofollow = true;
 345                                                         Channel::JoinUser(user, redir->targetchan.c_str(), false, "", false, ServerInstance->Time());
 346                                                         nofollow = false;
 347                                                         return MOD_RES_DENY;
 348                                                 }
 349                                         }
 350                                 }
 351                         }
 352                 }
 353                 return MOD_RES_PASSTHRU;
 354         }
 355
 356         virtual ~ModuleBanRedirect()
 357         {
 358                 /* XXX is this the best place to do this? */
 359                 if (!ServerInstance->Modes->DelModeWatcher(&re))
 360                         ServerInstance->Logs->Log("m_banredirect.so", DEBUG, "Failed to delete modewatcher!");
 361         }
 362
 363         virtual Version GetVersion()
 364         {
 365                 return Version("Allows an extended ban (+b) syntax redirecting banned users to another channel", VF_COMMON|VF_VENDOR);
 366         }
 367 };
 368
 369 MODULE_INIT(ModuleBanRedirect)