src/modules/m_dnsbl.cpp

   1 /*
   2  * InspIRCd -- Internet Relay Chat Daemon
   3  *
   4  *   Copyright (C) 2009-2010 Daniel De Graaf <danieldg@inspircd.org>
   5  *   Copyright (C) 2006-2008 Robin Burchell <robin+git@viroteck.net>
   6  *   Copyright (C) 2007 Craig Edwards <craigedwards@brainbox.cc>
   7  *   Copyright (C) 2006-2007 Dennis Friis <peavey@inspircd.org>
   8  *   Copyright (C) 2007 John Brooks <john.brooks@dereferenced.net>
   9  *
  10  * This file is part of InspIRCd.  InspIRCd is free software: you can
  11  * redistribute it and/or modify it under the terms of the GNU General Public
  12  * License as published by the Free Software Foundation, version 2.
  13  *
  14  * This program is distributed in the hope that it will be useful, but WITHOUT
  15  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  16  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  17  * details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21  */
  22
  23
  24 #include "inspircd.h"
  25 #include "xline.h"
  26 #include "modules/dns.h"
  27
  28 /* Class holding data for a single entry */
  29 class DNSBLConfEntry : public refcountbase
  30 {
  31         public:
  32                 enum EnumBanaction { I_UNKNOWN, I_KILL, I_ZLINE, I_KLINE, I_GLINE, I_MARK };
  33                 enum EnumType { A_RECORD, A_BITMASK };
  34                 std::string name, ident, host, domain, reason;
  35                 EnumBanaction banaction;
  36                 EnumType type;
  37                 long duration;
  38                 int bitmask;
  39                 unsigned char records[256];
  40                 unsigned long stats_hits, stats_misses;
  41                 DNSBLConfEntry(): type(A_BITMASK),duration(86400),bitmask(0),stats_hits(0), stats_misses(0) {}
  42 };
  43
  44
  45 /** Resolver for CGI:IRC hostnames encoded in ident/GECOS
  46  */
  47 class DNSBLResolver : public DNS::Request
  48 {
  49         std::string theiruid;
  50         LocalStringExt& nameExt;
  51         LocalIntExt& countExt;
  52         reference<DNSBLConfEntry> ConfEntry;
  53
  54  public:
  55
  56         DNSBLResolver(DNS::Manager *mgr, Module *me, LocalStringExt& match, LocalIntExt& ctr, const std::string &hostname, LocalUser* u, reference<DNSBLConfEntry> conf)
  57                 : DNS::Request(mgr, me, hostname, DNS::QUERY_A, true), theiruid(u->uuid), nameExt(match), countExt(ctr), ConfEntry(conf)
  58         {
  59         }
  60
  61         /* Note: This may be called multiple times for multiple A record results */
  62         void OnLookupComplete(const DNS::Query *r) CXX11_OVERRIDE
  63         {
  64                 /* Check the user still exists */
  65                 LocalUser* them = (LocalUser*)ServerInstance->FindUUID(theiruid);
  66                 if (!them)
  67                         return;
  68
  69                 const DNS::ResourceRecord* const ans_record = r->FindAnswerOfType(DNS::QUERY_A);
  70                 if (!ans_record)
  71                         return;
  72
  73                 int i = countExt.get(them);
  74                 if (i)
  75                         countExt.set(them, i - 1);
  76
  77                 // Now we calculate the bitmask: 256*(256*(256*a+b)+c)+d
  78
  79                 unsigned int bitmask = 0, record = 0;
  80                 bool match = false;
  81                 in_addr resultip;
  82
  83                 inet_aton(ans_record->rdata.c_str(), &resultip);
  84
  85                 switch (ConfEntry->type)
  86                 {
  87                         case DNSBLConfEntry::A_BITMASK:
  88                                 bitmask = resultip.s_addr >> 24; /* Last octet (network byte order) */
  89                                 bitmask &= ConfEntry->bitmask;
  90                                 match = (bitmask != 0);
  91                         break;
  92                         case DNSBLConfEntry::A_RECORD:
  93                                 record = resultip.s_addr >> 24; /* Last octet */
  94                                 match = (ConfEntry->records[record] == 1);
  95                         break;
  96                 }
  97
  98                 if (match)
  99                 {
 100                         std::string reason = ConfEntry->reason;
 101                         std::string::size_type x = reason.find("%ip%");
 102                         while (x != std::string::npos)
 103                         {
 104                                 reason.erase(x, 4);
 105                                 reason.insert(x, them->GetIPString());
 106                                 x = reason.find("%ip%");
 107                         }
 108
 109                         ConfEntry->stats_hits++;
 110
 111                         switch (ConfEntry->banaction)
 112                         {
 113                                 case DNSBLConfEntry::I_KILL:
 114                                 {
 115                                         ServerInstance->Users->QuitUser(them, "Killed (" + reason + ")");
 116                                         break;
 117                                 }
 118                                 case DNSBLConfEntry::I_MARK:
 119                                 {
 120                                         if (!ConfEntry->ident.empty())
 121                                         {
 122                                                 them->WriteNumeric(304, "Your ident has been set to " + ConfEntry->ident + " because you matched " + reason);
 123                                                 them->ChangeIdent(ConfEntry->ident);
 124                                         }
 125
 126                                         if (!ConfEntry->host.empty())
 127                                         {
 128                                                 them->WriteNumeric(304, "Your host has been set to " + ConfEntry->host + " because you matched " + reason);
 129                                                 them->ChangeDisplayedHost(ConfEntry->host);
 130                                         }
 131
 132                                         nameExt.set(them, ConfEntry->name);
 133                                         break;
 134                                 }
 135                                 case DNSBLConfEntry::I_KLINE:
 136                                 {
 137                                         KLine* kl = new KLine(ServerInstance->Time(), ConfEntry->duration, ServerInstance->Config->ServerName.c_str(), reason.c_str(),
 138                                                         "*", them->GetIPString());
 139                                         if (ServerInstance->XLines->AddLine(kl,NULL))
 140                                         {
 141                                                 std::string timestr = InspIRCd::TimeString(kl->expiry);
 142                                                 ServerInstance->SNO->WriteGlobalSno('x',"K:line added due to DNSBL match on *@%s to expire on %s: %s",
 143                                                         them->GetIPString().c_str(), timestr.c_str(), reason.c_str());
 144                                                 ServerInstance->XLines->ApplyLines();
 145                                         }
 146                                         else
 147                                         {
 148                                                 delete kl;
 149                                                 return;
 150                                         }
 151                                         break;
 152                                 }
 153                                 case DNSBLConfEntry::I_GLINE:
 154                                 {
 155                                         GLine* gl = new GLine(ServerInstance->Time(), ConfEntry->duration, ServerInstance->Config->ServerName.c_str(), reason.c_str(),
 156                                                         "*", them->GetIPString());
 157                                         if (ServerInstance->XLines->AddLine(gl,NULL))
 158                                         {
 159                                                 std::string timestr = InspIRCd::TimeString(gl->expiry);
 160                                                 ServerInstance->SNO->WriteGlobalSno('x',"G:line added due to DNSBL match on *@%s to expire on %s: %s",
 161                                                         them->GetIPString().c_str(), timestr.c_str(), reason.c_str());
 162                                                 ServerInstance->XLines->ApplyLines();
 163                                         }
 164                                         else
 165                                         {
 166                                                 delete gl;
 167                                                 return;
 168                                         }
 169                                         break;
 170                                 }
 171                                 case DNSBLConfEntry::I_ZLINE:
 172                                 {
 173                                         ZLine* zl = new ZLine(ServerInstance->Time(), ConfEntry->duration, ServerInstance->Config->ServerName.c_str(), reason.c_str(),
 174                                                         them->GetIPString());
 175                                         if (ServerInstance->XLines->AddLine(zl,NULL))
 176                                         {
 177                                                 std::string timestr = InspIRCd::TimeString(zl->expiry);
 178                                                 ServerInstance->SNO->WriteGlobalSno('x',"Z:line added due to DNSBL match on *@%s to expire on %s: %s",
 179                                                         them->GetIPString().c_str(), timestr.c_str(), reason.c_str());
 180                                                 ServerInstance->XLines->ApplyLines();
 181                                         }
 182                                         else
 183                                         {
 184                                                 delete zl;
 185                                                 return;
 186                                         }
 187                                         break;
 188                                 }
 189                                 case DNSBLConfEntry::I_UNKNOWN:
 190                                 default:
 191                                         break;
 192                         }
 193
 194                         ServerInstance->SNO->WriteGlobalSno('a', "Connecting user %s%s detected as being on a DNS blacklist (%s) with result %d", them->nick.empty() ? "<unknown>" : "", them->GetFullRealHost().c_str(), ConfEntry->domain.c_str(), (ConfEntry->type==DNSBLConfEntry::A_BITMASK) ? bitmask : record);
 195                 }
 196                 else
 197                         ConfEntry->stats_misses++;
 198         }
 199
 200         void OnError(const DNS::Query *q) CXX11_OVERRIDE
 201         {
 202                 LocalUser* them = (LocalUser*)ServerInstance->FindUUID(theiruid);
 203                 if (!them)
 204                         return;
 205
 206                 int i = countExt.get(them);
 207                 if (i)
 208                         countExt.set(them, i - 1);
 209
 210                 if (q->error == DNS::ERROR_NO_RECORDS || q->error == DNS::ERROR_DOMAIN_NOT_FOUND)
 211                         ConfEntry->stats_misses++;
 212         }
 213 };
 214
 215 class ModuleDNSBL : public Module
 216 {
 217         std::vector<reference<DNSBLConfEntry> > DNSBLConfEntries;
 218         dynamic_reference<DNS::Manager> DNS;
 219         LocalStringExt nameExt;
 220         LocalIntExt countExt;
 221
 222         /*
 223          *      Convert a string to EnumBanaction
 224          */
 225         DNSBLConfEntry::EnumBanaction str2banaction(const std::string &action)
 226         {
 227                 if(action.compare("KILL")==0)
 228                         return DNSBLConfEntry::I_KILL;
 229                 if(action.compare("KLINE")==0)
 230                         return DNSBLConfEntry::I_KLINE;
 231                 if(action.compare("ZLINE")==0)
 232                         return DNSBLConfEntry::I_ZLINE;
 233                 if(action.compare("GLINE")==0)
 234                         return DNSBLConfEntry::I_GLINE;
 235                 if(action.compare("MARK")==0)
 236                         return DNSBLConfEntry::I_MARK;
 237
 238                 return DNSBLConfEntry::I_UNKNOWN;
 239         }
 240  public:
 241         ModuleDNSBL()
 242                 : DNS(this, "DNS")
 243                 , nameExt("dnsbl_match", ExtensionItem::EXT_USER, this)
 244                 , countExt("dnsbl_pending", ExtensionItem::EXT_USER, this)
 245         {
 246         }
 247
 248         Version GetVersion() CXX11_OVERRIDE
 249         {
 250                 return Version("Provides handling of DNS blacklists", VF_VENDOR);
 251         }
 252
 253         /** Fill our conf vector with data
 254          */
 255         void ReadConfig(ConfigStatus& status) CXX11_OVERRIDE
 256         {
 257                 DNSBLConfEntries.clear();
 258
 259                 ConfigTagList dnsbls = ServerInstance->Config->ConfTags("dnsbl");
 260                 for(ConfigIter i = dnsbls.first; i != dnsbls.second; ++i)
 261                 {
 262                         ConfigTag* tag = i->second;
 263                         reference<DNSBLConfEntry> e = new DNSBLConfEntry();
 264
 265                         e->name = tag->getString("name");
 266                         e->ident = tag->getString("ident");
 267                         e->host = tag->getString("host");
 268                         e->reason = tag->getString("reason");
 269                         e->domain = tag->getString("domain");
 270
 271                         if (tag->getString("type") == "bitmask")
 272                         {
 273                                 e->type = DNSBLConfEntry::A_BITMASK;
 274                                 e->bitmask = tag->getInt("bitmask");
 275                         }
 276                         else
 277                         {
 278                                 memset(e->records, 0, sizeof(e->records));
 279                                 e->type = DNSBLConfEntry::A_RECORD;
 280                                 irc::portparser portrange(tag->getString("records"), false);
 281                                 long item = -1;
 282                                 while ((item = portrange.GetToken()))
 283                                         e->records[item] = 1;
 284                         }
 285
 286                         e->banaction = str2banaction(tag->getString("action"));
 287                         e->duration = tag->getDuration("duration", 60, 1);
 288
 289                         /* Use portparser for record replies */
 290
 291                         /* yeah, logic here is a little messy */
 292                         if ((e->bitmask <= 0) && (DNSBLConfEntry::A_BITMASK == e->type))
 293                         {
 294                                 std::string location = tag->getTagLocation();
 295                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(%s): invalid bitmask", location.c_str());
 296                         }
 297                         else if (e->name.empty())
 298                         {
 299                                 std::string location = tag->getTagLocation();
 300                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(%s): Invalid name", location.c_str());
 301                         }
 302                         else if (e->domain.empty())
 303                         {
 304                                 std::string location = tag->getTagLocation();
 305                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(%s): Invalid domain", location.c_str());
 306                         }
 307                         else if (e->banaction == DNSBLConfEntry::I_UNKNOWN)
 308                         {
 309                                 std::string location = tag->getTagLocation();
 310                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(%s): Invalid banaction", location.c_str());
 311                         }
 312                         else
 313                         {
 314                                 if (e->reason.empty())
 315                                 {
 316                                         std::string location = tag->getTagLocation();
 317                                         ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(%s): empty reason, using defaults", location.c_str());
 318                                         e->reason = "Your IP has been blacklisted.";
 319                                 }
 320
 321                                 /* add it, all is ok */
 322                                 DNSBLConfEntries.push_back(e);
 323                         }
 324                 }
 325         }
 326
 327         void OnSetUserIP(LocalUser* user) CXX11_OVERRIDE
 328         {
 329                 if ((user->exempt) || !DNS)
 330                         return;
 331
 332                 if (user->MyClass)
 333                 {
 334                         if (!user->MyClass->config->getBool("usednsbl", true))
 335                                 return;
 336                 }
 337                 else
 338                         ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "User has no connect class in OnSetUserIP");
 339
 340                 std::string reversedip;
 341                 if (user->client_sa.sa.sa_family == AF_INET)
 342                 {
 343                         unsigned int a, b, c, d;
 344                         d = (unsigned int) (user->client_sa.in4.sin_addr.s_addr >> 24) & 0xFF;
 345                         c = (unsigned int) (user->client_sa.in4.sin_addr.s_addr >> 16) & 0xFF;
 346                         b = (unsigned int) (user->client_sa.in4.sin_addr.s_addr >> 8) & 0xFF;
 347                         a = (unsigned int) user->client_sa.in4.sin_addr.s_addr & 0xFF;
 348
 349                         reversedip = ConvToStr(d) + "." + ConvToStr(c) + "." + ConvToStr(b) + "." + ConvToStr(a);
 350                 }
 351                 else if (user->client_sa.sa.sa_family == AF_INET6)
 352                 {
 353                         const unsigned char* ip = user->client_sa.in6.sin6_addr.s6_addr;
 354
 355                         std::string buf = BinToHex(ip, 16);
 356                         for (std::string::const_reverse_iterator it = buf.rbegin(); it != buf.rend(); ++it)
 357                         {
 358                                 reversedip.push_back(*it);
 359                                 reversedip.push_back('.');
 360                         }
 361                 }
 362                 else
 363                         return;
 364
 365                 ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Reversed IP %s -> %s", user->GetIPString().c_str(), reversedip.c_str());
 366
 367                 countExt.set(user, DNSBLConfEntries.size());
 368
 369                 // For each DNSBL, we will run through this lookup
 370                 for (unsigned i = 0; i < DNSBLConfEntries.size(); ++i)
 371                 {
 372                         // Fill hostname with a dnsbl style host (d.c.b.a.domain.tld)
 373                         std::string hostname = reversedip + "." + DNSBLConfEntries[i]->domain;
 374
 375                         /* now we'd need to fire off lookups for `hostname'. */
 376                         DNSBLResolver *r = new DNSBLResolver(*this->DNS, this, nameExt, countExt, hostname, user, DNSBLConfEntries[i]);
 377                         try
 378                         {
 379                                 this->DNS->Process(r);
 380                         }
 381                         catch (DNS::Exception &ex)
 382                         {
 383                                 delete r;
 384                                 ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, ex.GetReason());
 385                         }
 386
 387                         if (user->quitting)
 388                                 break;
 389                 }
 390         }
 391
 392         ModResult OnSetConnectClass(LocalUser* user, ConnectClass* myclass) CXX11_OVERRIDE
 393         {
 394                 std::string dnsbl;
 395                 if (!myclass->config->readString("dnsbl", dnsbl))
 396                         return MOD_RES_PASSTHRU;
 397                 std::string* match = nameExt.get(user);
 398                 std::string myname = match ? *match : "";
 399                 if (dnsbl == myname)
 400                         return MOD_RES_PASSTHRU;
 401                 return MOD_RES_DENY;
 402         }
 403
 404         ModResult OnCheckReady(LocalUser *user) CXX11_OVERRIDE
 405         {
 406                 if (countExt.get(user))
 407                         return MOD_RES_DENY;
 408                 return MOD_RES_PASSTHRU;
 409         }
 410
 411         ModResult OnStats(Stats::Context& stats) CXX11_OVERRIDE
 412         {
 413                 if (stats.GetSymbol() != 'd')
 414                         return MOD_RES_PASSTHRU;
 415
 416                 unsigned long total_hits = 0, total_misses = 0;
 417
 418                 for (std::vector<reference<DNSBLConfEntry> >::const_iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); ++i)
 419                 {
 420                         total_hits += (*i)->stats_hits;
 421                         total_misses += (*i)->stats_misses;
 422
 423                         stats.AddRow(304, "DNSBLSTATS DNSbl \"" + (*i)->name + "\" had " +
 424                                         ConvToStr((*i)->stats_hits) + " hits and " + ConvToStr((*i)->stats_misses) + " misses");
 425                 }
 426
 427                 stats.AddRow(304, "DNSBLSTATS Total hits: " + ConvToStr(total_hits));
 428                 stats.AddRow(304, "DNSBLSTATS Total misses: " + ConvToStr(total_misses));
 429
 430                 return MOD_RES_PASSTHRU;
 431         }
 432 };
 433
 434 MODULE_INIT(ModuleDNSBL)