src/modules/m_dnsbl.cpp

   1 /*
   2  * InspIRCd -- Internet Relay Chat Daemon
   3  *
   4  *   Copyright (C) 2018-2020 Matt Schatz <genius3000@g3k.solutions>
   5  *   Copyright (C) 2018-2019 linuxdaemon <linuxdaemon.irc@gmail.com>
   6  *   Copyright (C) 2013, 2016-2020 Sadie Powell <sadie@witchery.services>
   7  *   Copyright (C) 2013, 2015-2016 Adam <Adam@anope.org>
   8  *   Copyright (C) 2012-2016 Attila Molnar <attilamolnar@hush.com>
   9  *   Copyright (C) 2012, 2018 Robby <robby@chatbelgie.be>
  10  *   Copyright (C) 2009-2010 Daniel De Graaf <danieldg@inspircd.org>
  11  *   Copyright (C) 2007, 2010 Craig Edwards <brain@inspircd.org>
  12  *   Copyright (C) 2007 Dennis Friis <peavey@inspircd.org>
  13  *   Copyright (C) 2006-2009 Robin Burchell <robin+git@viroteck.net>
  14  *
  15  * This file is part of InspIRCd.  InspIRCd is free software: you can
  16  * redistribute it and/or modify it under the terms of the GNU General Public
  17  * License as published by the Free Software Foundation, version 2.
  18  *
  19  * This program is distributed in the hope that it will be useful, but WITHOUT
  20  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  21  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  22  * details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  26  */
  27
  28
  29 #include "inspircd.h"
  30 #include "xline.h"
  31 #include "modules/dns.h"
  32 #include "modules/stats.h"
  33
  34 /* Class holding data for a single entry */
  35 class DNSBLConfEntry : public refcountbase
  36 {
  37         public:
  38                 enum EnumBanaction { I_UNKNOWN, I_KILL, I_ZLINE, I_KLINE, I_GLINE, I_MARK };
  39                 enum EnumType { A_RECORD, A_BITMASK };
  40                 std::string name, ident, host, domain, reason;
  41                 EnumBanaction banaction;
  42                 EnumType type;
  43                 unsigned long duration;
  44                 unsigned int bitmask;
  45                 unsigned char records[256];
  46                 unsigned long stats_hits, stats_misses;
  47                 DNSBLConfEntry(): type(A_BITMASK),duration(86400),bitmask(0),stats_hits(0), stats_misses(0) {}
  48 };
  49
  50
  51 /** Resolver for CGI:IRC hostnames encoded in ident/real name
  52  */
  53 class DNSBLResolver : public DNS::Request
  54 {
  55  private:
  56         irc::sockets::sockaddrs theirsa;
  57         std::string theiruid;
  58         LocalStringExt& nameExt;
  59         LocalIntExt& countExt;
  60         reference<DNSBLConfEntry> ConfEntry;
  61
  62  public:
  63         DNSBLResolver(DNS::Manager *mgr, Module *me, LocalStringExt& match, LocalIntExt& ctr, const std::string &hostname, LocalUser* u, reference<DNSBLConfEntry> conf)
  64                 : DNS::Request(mgr, me, hostname, DNS::QUERY_A, true)
  65                 , theirsa(u->client_sa)
  66                 , theiruid(u->uuid)
  67                 , nameExt(match)
  68                 , countExt(ctr)
  69                 , ConfEntry(conf)
  70         {
  71         }
  72
  73         /* Note: This may be called multiple times for multiple A record results */
  74         void OnLookupComplete(const DNS::Query *r) CXX11_OVERRIDE
  75         {
  76                 /* Check the user still exists */
  77                 LocalUser* them = IS_LOCAL(ServerInstance->FindUUID(theiruid));
  78                 if (!them || them->client_sa != theirsa)
  79                         return;
  80
  81                 int i = countExt.get(them);
  82                 if (i)
  83                         countExt.set(them, i - 1);
  84
  85                 // The DNSBL reply must contain an A result.
  86                 const DNS::ResourceRecord* const ans_record = r->FindAnswerOfType(DNS::QUERY_A);
  87                 if (!ans_record)
  88                 {
  89                         ConfEntry->stats_misses++;
  90                         ServerInstance->SNO->WriteGlobalSno('d', "%s returned an result with no IPv4 address.",
  91                                 ConfEntry->name.c_str());
  92                         return;
  93                 }
  94
  95                 // The DNSBL reply must be a valid IPv4 address.
  96                 in_addr resultip;
  97                 if (inet_pton(AF_INET, ans_record->rdata.c_str(), &resultip) != 1)
  98                 {
  99                         ConfEntry->stats_misses++;
 100                         ServerInstance->SNO->WriteGlobalSno('d', "%s returned an invalid IPv4 address: %s",
 101                                 ConfEntry->name.c_str(), ans_record->rdata.c_str());
 102                         return;
 103                 }
 104
 105                 // The DNSBL reply should be in the 127.0.0.0/8 range.
 106                 if ((resultip.s_addr & 0xFF) != 127)
 107                 {
 108                         ConfEntry->stats_misses++;
 109                         ServerInstance->SNO->WriteGlobalSno('d', "%s returned an IPv4 address which is outside of the 127.0.0.0/8 subnet: %s",
 110                                 ConfEntry->name.c_str(), ans_record->rdata.c_str());
 111                         return;
 112                 }
 113
 114                 bool match = false;
 115                 unsigned int result = 0;
 116                 switch (ConfEntry->type)
 117                 {
 118                         case DNSBLConfEntry::A_BITMASK:
 119                         {
 120                                 result = (resultip.s_addr >> 24) & ConfEntry->bitmask;
 121                                 match = (result != 0);
 122                                 break;
 123                         }
 124                         case DNSBLConfEntry::A_RECORD:
 125                         {
 126                                 result = resultip.s_addr >> 24;
 127                                 match = (ConfEntry->records[result] == 1);
 128                                 break;
 129                         }
 130                 }
 131
 132                 if (match)
 133                 {
 134                         std::string reason = ConfEntry->reason;
 135                         std::string::size_type x = reason.find("%ip%");
 136                         while (x != std::string::npos)
 137                         {
 138                                 reason.erase(x, 4);
 139                                 reason.insert(x, them->GetIPString());
 140                                 x = reason.find("%ip%");
 141                         }
 142
 143                         ConfEntry->stats_hits++;
 144
 145                         switch (ConfEntry->banaction)
 146                         {
 147                                 case DNSBLConfEntry::I_KILL:
 148                                 {
 149                                         ServerInstance->Users->QuitUser(them, "Killed (" + reason + ")");
 150                                         break;
 151                                 }
 152                                 case DNSBLConfEntry::I_MARK:
 153                                 {
 154                                         if (!ConfEntry->ident.empty())
 155                                         {
 156                                                 them->WriteNotice("Your ident has been set to " + ConfEntry->ident + " because you matched " + reason);
 157                                                 them->ChangeIdent(ConfEntry->ident);
 158                                         }
 159
 160                                         if (!ConfEntry->host.empty())
 161                                         {
 162                                                 them->WriteNotice("Your host has been set to " + ConfEntry->host + " because you matched " + reason);
 163                                                 them->ChangeDisplayedHost(ConfEntry->host);
 164                                         }
 165
 166                                         nameExt.set(them, ConfEntry->name);
 167                                         break;
 168                                 }
 169                                 case DNSBLConfEntry::I_KLINE:
 170                                 {
 171                                         KLine* kl = new KLine(ServerInstance->Time(), ConfEntry->duration, ServerInstance->Config->ServerName.c_str(), reason.c_str(),
 172                                                         "*", them->GetIPString());
 173                                         if (ServerInstance->XLines->AddLine(kl,NULL))
 174                                         {
 175                                                 ServerInstance->SNO->WriteToSnoMask('x', "K-line added due to DNSBL match on *@%s to expire in %s (on %s): %s",
 176                                                         them->GetIPString().c_str(), InspIRCd::DurationString(kl->duration).c_str(),
 177                                                         InspIRCd::TimeString(kl->expiry).c_str(), reason.c_str());
 178                                                 ServerInstance->XLines->ApplyLines();
 179                                         }
 180                                         else
 181                                         {
 182                                                 delete kl;
 183                                                 return;
 184                                         }
 185                                         break;
 186                                 }
 187                                 case DNSBLConfEntry::I_GLINE:
 188                                 {
 189                                         GLine* gl = new GLine(ServerInstance->Time(), ConfEntry->duration, ServerInstance->Config->ServerName.c_str(), reason.c_str(),
 190                                                         "*", them->GetIPString());
 191                                         if (ServerInstance->XLines->AddLine(gl,NULL))
 192                                         {
 193                                                 ServerInstance->SNO->WriteToSnoMask('x', "G-line added due to DNSBL match on *@%s to expire in %s (on %s): %s",
 194                                                         them->GetIPString().c_str(), InspIRCd::DurationString(gl->duration).c_str(),
 195                                                         InspIRCd::TimeString(gl->expiry).c_str(), reason.c_str());
 196                                                 ServerInstance->XLines->ApplyLines();
 197                                         }
 198                                         else
 199                                         {
 200                                                 delete gl;
 201                                                 return;
 202                                         }
 203                                         break;
 204                                 }
 205                                 case DNSBLConfEntry::I_ZLINE:
 206                                 {
 207                                         ZLine* zl = new ZLine(ServerInstance->Time(), ConfEntry->duration, ServerInstance->Config->ServerName.c_str(), reason.c_str(),
 208                                                         them->GetIPString());
 209                                         if (ServerInstance->XLines->AddLine(zl,NULL))
 210                                         {
 211                                                 ServerInstance->SNO->WriteToSnoMask('x', "Z-line added due to DNSBL match on %s to expire in %s (on %s): %s",
 212                                                         them->GetIPString().c_str(), InspIRCd::DurationString(zl->duration).c_str(),
 213                                                         InspIRCd::TimeString(zl->expiry).c_str(), reason.c_str());
 214                                                 ServerInstance->XLines->ApplyLines();
 215                                         }
 216                                         else
 217                                         {
 218                                                 delete zl;
 219                                                 return;
 220                                         }
 221                                         break;
 222                                 }
 223                                 case DNSBLConfEntry::I_UNKNOWN:
 224                                 default:
 225                                         break;
 226                         }
 227
 228                         ServerInstance->SNO->WriteGlobalSno('d', "Connecting user %s (%s) detected as being on the '%s' DNS blacklist with result %d",
 229                                 them->GetFullRealHost().c_str(), them->GetIPString().c_str(), ConfEntry->name.c_str(), result);
 230                 }
 231                 else
 232                         ConfEntry->stats_misses++;
 233         }
 234
 235         void OnError(const DNS::Query *q) CXX11_OVERRIDE
 236         {
 237                 LocalUser* them = IS_LOCAL(ServerInstance->FindUUID(theiruid));
 238                 if (!them || them->client_sa != theirsa)
 239                         return;
 240
 241                 int i = countExt.get(them);
 242                 if (i)
 243                         countExt.set(them, i - 1);
 244
 245                 if (q->error == DNS::ERROR_NO_RECORDS || q->error == DNS::ERROR_DOMAIN_NOT_FOUND)
 246                 {
 247                         ConfEntry->stats_misses++;
 248                         return;
 249                 }
 250
 251                 ServerInstance->SNO->WriteGlobalSno('d', "An error occurred whilst checking whether %s (%s) is on the '%s' DNS blacklist: %s",
 252                         them->GetFullRealHost().c_str(), them->GetIPString().c_str(), ConfEntry->name.c_str(), this->manager->GetErrorStr(q->error).c_str());
 253         }
 254 };
 255
 256 typedef std::vector<reference<DNSBLConfEntry> > DNSBLConfList;
 257
 258 class ModuleDNSBL : public Module, public Stats::EventListener
 259 {
 260         DNSBLConfList DNSBLConfEntries;
 261         dynamic_reference<DNS::Manager> DNS;
 262         LocalStringExt nameExt;
 263         LocalIntExt countExt;
 264
 265         /*
 266          *      Convert a string to EnumBanaction
 267          */
 268         DNSBLConfEntry::EnumBanaction str2banaction(const std::string &action)
 269         {
 270                 if (stdalgo::string::equalsci(action, "kill"))
 271                         return DNSBLConfEntry::I_KILL;
 272                 if (stdalgo::string::equalsci(action, "kline"))
 273                         return DNSBLConfEntry::I_KLINE;
 274                 if (stdalgo::string::equalsci(action, "zline"))
 275                         return DNSBLConfEntry::I_ZLINE;
 276                 if (stdalgo::string::equalsci(action, "gline"))
 277                         return DNSBLConfEntry::I_GLINE;
 278                 if (stdalgo::string::equalsci(action, "mark"))
 279                         return DNSBLConfEntry::I_MARK;
 280                 return DNSBLConfEntry::I_UNKNOWN;
 281         }
 282  public:
 283         ModuleDNSBL()
 284                 : Stats::EventListener(this)
 285                 , DNS(this, "DNS")
 286                 , nameExt("dnsbl_match", ExtensionItem::EXT_USER, this)
 287                 , countExt("dnsbl_pending", ExtensionItem::EXT_USER, this)
 288         {
 289         }
 290
 291         void init() CXX11_OVERRIDE
 292         {
 293                 ServerInstance->SNO->EnableSnomask('d', "DNSBL");
 294         }
 295
 296         void Prioritize() CXX11_OVERRIDE
 297         {
 298                 Module* corexline = ServerInstance->Modules->Find("core_xline");
 299                 ServerInstance->Modules->SetPriority(this, I_OnSetUserIP, PRIORITY_AFTER, corexline);
 300         }
 301
 302         Version GetVersion() CXX11_OVERRIDE
 303         {
 304                 return Version("Allows the server administrator to check the IP address of connecting users against a DNSBL.", VF_VENDOR);
 305         }
 306
 307         /** Fill our conf vector with data
 308          */
 309         void ReadConfig(ConfigStatus& status) CXX11_OVERRIDE
 310         {
 311                 DNSBLConfList newentries;
 312
 313                 ConfigTagList dnsbls = ServerInstance->Config->ConfTags("dnsbl");
 314                 for(ConfigIter i = dnsbls.first; i != dnsbls.second; ++i)
 315                 {
 316                         ConfigTag* tag = i->second;
 317                         reference<DNSBLConfEntry> e = new DNSBLConfEntry();
 318
 319                         e->name = tag->getString("name");
 320                         e->ident = tag->getString("ident");
 321                         e->host = tag->getString("host");
 322                         e->reason = tag->getString("reason", "Your IP has been blacklisted.", 1);
 323                         e->domain = tag->getString("domain");
 324
 325                         if (stdalgo::string::equalsci(tag->getString("type"), "bitmask"))
 326                         {
 327                                 e->type = DNSBLConfEntry::A_BITMASK;
 328                                 e->bitmask = tag->getUInt("bitmask", 0, 0, UINT_MAX);
 329                         }
 330                         else
 331                         {
 332                                 memset(e->records, 0, sizeof(e->records));
 333                                 e->type = DNSBLConfEntry::A_RECORD;
 334                                 irc::portparser portrange(tag->getString("records"), false);
 335                                 long item = -1;
 336                                 while ((item = portrange.GetToken()))
 337                                         e->records[item] = 1;
 338                         }
 339
 340                         e->banaction = str2banaction(tag->getString("action"));
 341                         e->duration = tag->getDuration("duration", 60, 1);
 342
 343                         /* Use portparser for record replies */
 344
 345                         /* yeah, logic here is a little messy */
 346                         if ((e->bitmask <= 0) && (DNSBLConfEntry::A_BITMASK == e->type))
 347                         {
 348                                 throw ModuleException("Invalid <dnsbl:bitmask> at " + tag->getTagLocation());
 349                         }
 350                         else if (e->name.empty())
 351                         {
 352                                 throw ModuleException("Empty <dnsbl:name> at " + tag->getTagLocation());
 353                         }
 354                         else if (e->domain.empty())
 355                         {
 356                                 throw ModuleException("Empty <dnsbl:domain> at " + tag->getTagLocation());
 357                         }
 358                         else if (e->banaction == DNSBLConfEntry::I_UNKNOWN)
 359                         {
 360                                 throw ModuleException("Unknown <dnsbl:action> at " + tag->getTagLocation());
 361                         }
 362                         else
 363                         {
 364                                 /* add it, all is ok */
 365                                 newentries.push_back(e);
 366                         }
 367                 }
 368
 369                 DNSBLConfEntries.swap(newentries);
 370         }
 371
 372         void OnSetUserIP(LocalUser* user) CXX11_OVERRIDE
 373         {
 374                 if (user->exempt || user->quitting || !DNS)
 375                         return;
 376
 377                 // Clients can't be in a DNSBL if they aren't connected via IPv4 or IPv6.
 378                 if (user->client_sa.family() != AF_INET && user->client_sa.family() != AF_INET6)
 379                         return;
 380
 381                 if (user->MyClass)
 382                 {
 383                         if (!user->MyClass->config->getBool("usednsbl", true))
 384                                 return;
 385                 }
 386                 else
 387                 {
 388                         ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "User has no connect class in OnSetUserIP");
 389                         return;
 390                 }
 391
 392                 std::string reversedip;
 393                 if (user->client_sa.family() == AF_INET)
 394                 {
 395                         unsigned int a, b, c, d;
 396                         d = (unsigned int) (user->client_sa.in4.sin_addr.s_addr >> 24) & 0xFF;
 397                         c = (unsigned int) (user->client_sa.in4.sin_addr.s_addr >> 16) & 0xFF;
 398                         b = (unsigned int) (user->client_sa.in4.sin_addr.s_addr >> 8) & 0xFF;
 399                         a = (unsigned int) user->client_sa.in4.sin_addr.s_addr & 0xFF;
 400
 401                         reversedip = ConvToStr(d) + "." + ConvToStr(c) + "." + ConvToStr(b) + "." + ConvToStr(a);
 402                 }
 403                 else if (user->client_sa.family() == AF_INET6)
 404                 {
 405                         const unsigned char* ip = user->client_sa.in6.sin6_addr.s6_addr;
 406
 407                         std::string buf = BinToHex(ip, 16);
 408                         for (std::string::const_reverse_iterator it = buf.rbegin(); it != buf.rend(); ++it)
 409                         {
 410                                 reversedip.push_back(*it);
 411                                 reversedip.push_back('.');
 412                         }
 413                         reversedip.erase(reversedip.length() - 1, 1);
 414                 }
 415                 else
 416                         return;
 417
 418                 ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Reversed IP %s -> %s", user->GetIPString().c_str(), reversedip.c_str());
 419
 420                 countExt.set(user, DNSBLConfEntries.size());
 421
 422                 // For each DNSBL, we will run through this lookup
 423                 for (unsigned i = 0; i < DNSBLConfEntries.size(); ++i)
 424                 {
 425                         // Fill hostname with a dnsbl style host (d.c.b.a.domain.tld)
 426                         std::string hostname = reversedip + "." + DNSBLConfEntries[i]->domain;
 427
 428                         /* now we'd need to fire off lookups for `hostname'. */
 429                         DNSBLResolver *r = new DNSBLResolver(*this->DNS, this, nameExt, countExt, hostname, user, DNSBLConfEntries[i]);
 430                         try
 431                         {
 432                                 this->DNS->Process(r);
 433                         }
 434                         catch (DNS::Exception &ex)
 435                         {
 436                                 delete r;
 437                                 ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, ex.GetReason());
 438                         }
 439
 440                         if (user->quitting)
 441                                 break;
 442                 }
 443         }
 444
 445         ModResult OnSetConnectClass(LocalUser* user, ConnectClass* myclass) CXX11_OVERRIDE
 446         {
 447                 std::string dnsbl;
 448                 if (!myclass->config->readString("dnsbl", dnsbl))
 449                         return MOD_RES_PASSTHRU;
 450
 451                 std::string* match = nameExt.get(user);
 452                 if (!match)
 453                 {
 454                         ServerInstance->Logs->Log("CONNECTCLASS", LOG_DEBUG, "The %s connect class is not suitable as it requires a DNSBL mark",
 455                                         myclass->GetName().c_str());
 456                         return MOD_RES_DENY;
 457                 }
 458
 459                 if (!InspIRCd::Match(*match, dnsbl))
 460                 {
 461                         ServerInstance->Logs->Log("CONNECTCLASS", LOG_DEBUG, "The %s connect class is not suitable as the DNSBL mark (%s) does not match %s",
 462                                         myclass->GetName().c_str(), match->c_str(), dnsbl.c_str());
 463                         return MOD_RES_DENY;
 464                 }
 465
 466                 return MOD_RES_PASSTHRU;
 467         }
 468
 469         ModResult OnCheckReady(LocalUser *user) CXX11_OVERRIDE
 470         {
 471                 if (countExt.get(user))
 472                         return MOD_RES_DENY;
 473                 return MOD_RES_PASSTHRU;
 474         }
 475
 476         ModResult OnStats(Stats::Context& stats) CXX11_OVERRIDE
 477         {
 478                 if (stats.GetSymbol() != 'd')
 479                         return MOD_RES_PASSTHRU;
 480
 481                 unsigned long total_hits = 0, total_misses = 0;
 482
 483                 for (std::vector<reference<DNSBLConfEntry> >::const_iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); ++i)
 484                 {
 485                         total_hits += (*i)->stats_hits;
 486                         total_misses += (*i)->stats_misses;
 487
 488                         stats.AddRow(304, "DNSBLSTATS DNSbl \"" + (*i)->name + "\" had " +
 489                                         ConvToStr((*i)->stats_hits) + " hits and " + ConvToStr((*i)->stats_misses) + " misses");
 490                 }
 491
 492                 stats.AddRow(304, "DNSBLSTATS Total hits: " + ConvToStr(total_hits));
 493                 stats.AddRow(304, "DNSBLSTATS Total misses: " + ConvToStr(total_misses));
 494
 495                 return MOD_RES_PASSTHRU;
 496         }
 497 };
 498
 499 MODULE_INIT(ModuleDNSBL)