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 #include "modules/stats.h"
  28
  29 /* Class holding data for a single entry */
  30 class DNSBLConfEntry : public refcountbase
  31 {
  32         public:
  33                 enum EnumBanaction { I_UNKNOWN, I_KILL, I_ZLINE, I_KLINE, I_GLINE, I_MARK };
  34                 enum EnumType { A_RECORD, A_BITMASK };
  35                 std::string name, ident, host, domain, reason;
  36                 EnumBanaction banaction;
  37                 EnumType type;
  38                 unsigned long duration;
  39                 unsigned int bitmask;
  40                 unsigned char records[256];
  41                 unsigned long stats_hits, stats_misses;
  42                 DNSBLConfEntry(): type(A_BITMASK),duration(86400),bitmask(0),stats_hits(0), stats_misses(0) {}
  43 };
  44
  45
  46 /** Resolver for CGI:IRC hostnames encoded in ident/real name
  47  */
  48 class DNSBLResolver : public DNS::Request
  49 {
  50  private:
  51         irc::sockets::sockaddrs theirsa;
  52         std::string theiruid;
  53         LocalStringExt& nameExt;
  54         LocalIntExt& countExt;
  55         reference<DNSBLConfEntry> ConfEntry;
  56
  57  public:
  58         DNSBLResolver(DNS::Manager *mgr, Module *me, LocalStringExt& match, LocalIntExt& ctr, const std::string &hostname, LocalUser* u, reference<DNSBLConfEntry> conf)
  59                 : DNS::Request(mgr, me, hostname, DNS::QUERY_A, true)
  60                 , theirsa(u->client_sa)
  61                 , theiruid(u->uuid)
  62                 , nameExt(match)
  63                 , countExt(ctr)
  64                 , ConfEntry(conf)
  65         {
  66         }
  67
  68         /* Note: This may be called multiple times for multiple A record results */
  69         void OnLookupComplete(const DNS::Query *r) CXX11_OVERRIDE
  70         {
  71                 /* Check the user still exists */
  72                 LocalUser* them = IS_LOCAL(ServerInstance->FindUUID(theiruid));
  73                 if (!them || them->client_sa != theirsa)
  74                         return;
  75
  76                 const DNS::ResourceRecord* const ans_record = r->FindAnswerOfType(DNS::QUERY_A);
  77                 if (!ans_record)
  78                         return;
  79
  80                 // All replies should be in 127.0.0.0/8
  81                 if (ans_record->rdata.compare(0, 4, "127.") != 0)
  82                 {
  83                         ServerInstance->SNO->WriteGlobalSno('d', "DNSBL: %s returned address outside of acceptable subnet 127.0.0.0/8: %s", ConfEntry->domain.c_str(), ans_record->rdata.c_str());
  84                         ConfEntry->stats_misses++;
  85                         return;
  86                 }
  87
  88                 int i = countExt.get(them);
  89                 if (i)
  90                         countExt.set(them, i - 1);
  91
  92                 // Now we calculate the bitmask: 256*(256*(256*a+b)+c)+d
  93
  94                 unsigned int bitmask = 0, record = 0;
  95                 bool match = false;
  96                 in_addr resultip;
  97
  98                 inet_pton(AF_INET, ans_record->rdata.c_str(), &resultip);
  99
 100                 switch (ConfEntry->type)
 101                 {
 102                         case DNSBLConfEntry::A_BITMASK:
 103                                 bitmask = resultip.s_addr >> 24; /* Last octet (network byte order) */
 104                                 bitmask &= ConfEntry->bitmask;
 105                                 match = (bitmask != 0);
 106                         break;
 107                         case DNSBLConfEntry::A_RECORD:
 108                                 record = resultip.s_addr >> 24; /* Last octet */
 109                                 match = (ConfEntry->records[record] == 1);
 110                         break;
 111                 }
 112
 113                 if (match)
 114                 {
 115                         std::string reason = ConfEntry->reason;
 116                         std::string::size_type x = reason.find("%ip%");
 117                         while (x != std::string::npos)
 118                         {
 119                                 reason.erase(x, 4);
 120                                 reason.insert(x, them->GetIPString());
 121                                 x = reason.find("%ip%");
 122                         }
 123
 124                         ConfEntry->stats_hits++;
 125
 126                         switch (ConfEntry->banaction)
 127                         {
 128                                 case DNSBLConfEntry::I_KILL:
 129                                 {
 130                                         ServerInstance->Users->QuitUser(them, "Killed (" + reason + ")");
 131                                         break;
 132                                 }
 133                                 case DNSBLConfEntry::I_MARK:
 134                                 {
 135                                         if (!ConfEntry->ident.empty())
 136                                         {
 137                                                 them->WriteNotice("Your ident has been set to " + ConfEntry->ident + " because you matched " + reason);
 138                                                 them->ChangeIdent(ConfEntry->ident);
 139                                         }
 140
 141                                         if (!ConfEntry->host.empty())
 142                                         {
 143                                                 them->WriteNotice("Your host has been set to " + ConfEntry->host + " because you matched " + reason);
 144                                                 them->ChangeDisplayedHost(ConfEntry->host);
 145                                         }
 146
 147                                         nameExt.set(them, ConfEntry->name);
 148                                         break;
 149                                 }
 150                                 case DNSBLConfEntry::I_KLINE:
 151                                 {
 152                                         KLine* kl = new KLine(ServerInstance->Time(), ConfEntry->duration, ServerInstance->Config->ServerName.c_str(), reason.c_str(),
 153                                                         "*", them->GetIPString());
 154                                         if (ServerInstance->XLines->AddLine(kl,NULL))
 155                                         {
 156                                                 ServerInstance->SNO->WriteGlobalSno('x', "K-line added due to DNSBL match on *@%s to expire in %s (on %s): %s",
 157                                                         them->GetIPString().c_str(), InspIRCd::DurationString(kl->duration).c_str(),
 158                                                         InspIRCd::TimeString(kl->expiry).c_str(), reason.c_str());
 159                                                 ServerInstance->XLines->ApplyLines();
 160                                         }
 161                                         else
 162                                         {
 163                                                 delete kl;
 164                                                 return;
 165                                         }
 166                                         break;
 167                                 }
 168                                 case DNSBLConfEntry::I_GLINE:
 169                                 {
 170                                         GLine* gl = new GLine(ServerInstance->Time(), ConfEntry->duration, ServerInstance->Config->ServerName.c_str(), reason.c_str(),
 171                                                         "*", them->GetIPString());
 172                                         if (ServerInstance->XLines->AddLine(gl,NULL))
 173                                         {
 174                                                 ServerInstance->SNO->WriteGlobalSno('x', "G-line added due to DNSBL match on *@%s to expire in %s (on %s): %s",
 175                                                         them->GetIPString().c_str(), InspIRCd::DurationString(gl->duration).c_str(),
 176                                                         InspIRCd::TimeString(gl->expiry).c_str(), reason.c_str());
 177                                                 ServerInstance->XLines->ApplyLines();
 178                                         }
 179                                         else
 180                                         {
 181                                                 delete gl;
 182                                                 return;
 183                                         }
 184                                         break;
 185                                 }
 186                                 case DNSBLConfEntry::I_ZLINE:
 187                                 {
 188                                         ZLine* zl = new ZLine(ServerInstance->Time(), ConfEntry->duration, ServerInstance->Config->ServerName.c_str(), reason.c_str(),
 189                                                         them->GetIPString());
 190                                         if (ServerInstance->XLines->AddLine(zl,NULL))
 191                                         {
 192                                                 ServerInstance->SNO->WriteGlobalSno('x', "Z-line added due to DNSBL match on %s to expire in %s (on %s): %s",
 193                                                         them->GetIPString().c_str(), InspIRCd::DurationString(zl->duration).c_str(),
 194                                                         InspIRCd::TimeString(zl->expiry).c_str(), reason.c_str());
 195                                                 ServerInstance->XLines->ApplyLines();
 196                                         }
 197                                         else
 198                                         {
 199                                                 delete zl;
 200                                                 return;
 201                                         }
 202                                         break;
 203                                 }
 204                                 case DNSBLConfEntry::I_UNKNOWN:
 205                                 default:
 206                                         break;
 207                         }
 208
 209                         ServerInstance->SNO->WriteGlobalSno('d', "Connecting user %s (%s) detected as being on the '%s' DNS blacklist with result %d",
 210                                 them->GetFullRealHost().c_str(), them->GetIPString().c_str(), ConfEntry->name.c_str(), (ConfEntry->type==DNSBLConfEntry::A_BITMASK) ? bitmask : record);
 211                 }
 212                 else
 213                         ConfEntry->stats_misses++;
 214         }
 215
 216         void OnError(const DNS::Query *q) CXX11_OVERRIDE
 217         {
 218                 LocalUser* them = IS_LOCAL(ServerInstance->FindUUID(theiruid));
 219                 if (!them || them->client_sa != theirsa)
 220                         return;
 221
 222                 int i = countExt.get(them);
 223                 if (i)
 224                         countExt.set(them, i - 1);
 225
 226                 if (q->error == DNS::ERROR_NO_RECORDS || q->error == DNS::ERROR_DOMAIN_NOT_FOUND)
 227                 {
 228                         ConfEntry->stats_misses++;
 229                         return;
 230                 }
 231
 232                 ServerInstance->SNO->WriteGlobalSno('d', "An error occurred whilst checking whether %s (%s) is on the '%s' DNS blacklist: %s",
 233                         them->GetFullRealHost().c_str(), them->GetIPString().c_str(), ConfEntry->name.c_str(), this->manager->GetErrorStr(q->error).c_str());
 234         }
 235 };
 236
 237 typedef std::vector<reference<DNSBLConfEntry> > DNSBLConfList;
 238
 239 class ModuleDNSBL : public Module, public Stats::EventListener
 240 {
 241         DNSBLConfList DNSBLConfEntries;
 242         dynamic_reference<DNS::Manager> DNS;
 243         LocalStringExt nameExt;
 244         LocalIntExt countExt;
 245
 246         /*
 247          *      Convert a string to EnumBanaction
 248          */
 249         DNSBLConfEntry::EnumBanaction str2banaction(const std::string &action)
 250         {
 251                 if(action.compare("KILL")==0)
 252                         return DNSBLConfEntry::I_KILL;
 253                 if(action.compare("KLINE")==0)
 254                         return DNSBLConfEntry::I_KLINE;
 255                 if(action.compare("ZLINE")==0)
 256                         return DNSBLConfEntry::I_ZLINE;
 257                 if(action.compare("GLINE")==0)
 258                         return DNSBLConfEntry::I_GLINE;
 259                 if(action.compare("MARK")==0)
 260                         return DNSBLConfEntry::I_MARK;
 261
 262                 return DNSBLConfEntry::I_UNKNOWN;
 263         }
 264  public:
 265         ModuleDNSBL()
 266                 : Stats::EventListener(this)
 267                 , DNS(this, "DNS")
 268                 , nameExt("dnsbl_match", ExtensionItem::EXT_USER, this)
 269                 , countExt("dnsbl_pending", ExtensionItem::EXT_USER, this)
 270         {
 271         }
 272
 273         void init() CXX11_OVERRIDE
 274         {
 275                 ServerInstance->SNO->EnableSnomask('d', "DNSBL");
 276         }
 277
 278         Version GetVersion() CXX11_OVERRIDE
 279         {
 280                 return Version("Provides handling of DNS blacklists", VF_VENDOR);
 281         }
 282
 283         /** Fill our conf vector with data
 284          */
 285         void ReadConfig(ConfigStatus& status) CXX11_OVERRIDE
 286         {
 287                 DNSBLConfList newentries;
 288
 289                 ConfigTagList dnsbls = ServerInstance->Config->ConfTags("dnsbl");
 290                 for(ConfigIter i = dnsbls.first; i != dnsbls.second; ++i)
 291                 {
 292                         ConfigTag* tag = i->second;
 293                         reference<DNSBLConfEntry> e = new DNSBLConfEntry();
 294
 295                         e->name = tag->getString("name");
 296                         e->ident = tag->getString("ident");
 297                         e->host = tag->getString("host");
 298                         e->reason = tag->getString("reason");
 299                         e->domain = tag->getString("domain");
 300
 301                         if (stdalgo::string::equalsci(tag->getString("type"), "bitmask"))
 302                         {
 303                                 e->type = DNSBLConfEntry::A_BITMASK;
 304                                 e->bitmask = tag->getUInt("bitmask", 0, 0, UINT_MAX);
 305                         }
 306                         else
 307                         {
 308                                 memset(e->records, 0, sizeof(e->records));
 309                                 e->type = DNSBLConfEntry::A_RECORD;
 310                                 irc::portparser portrange(tag->getString("records"), false);
 311                                 long item = -1;
 312                                 while ((item = portrange.GetToken()))
 313                                         e->records[item] = 1;
 314                         }
 315
 316                         e->banaction = str2banaction(tag->getString("action"));
 317                         e->duration = tag->getDuration("duration", 60, 1);
 318
 319                         /* Use portparser for record replies */
 320
 321                         /* yeah, logic here is a little messy */
 322                         if ((e->bitmask <= 0) && (DNSBLConfEntry::A_BITMASK == e->type))
 323                         {
 324                                 throw ModuleException("Invalid <dnsbl:bitmask> at " + tag->getTagLocation());
 325                         }
 326                         else if (e->name.empty())
 327                         {
 328                                 throw ModuleException("Empty <dnsbl:name> at " + tag->getTagLocation());
 329                         }
 330                         else if (e->domain.empty())
 331                         {
 332                                 throw ModuleException("Empty <dnsbl:domain> at " + tag->getTagLocation());
 333                         }
 334                         else if (e->banaction == DNSBLConfEntry::I_UNKNOWN)
 335                         {
 336                                 throw ModuleException("Unknown <dnsbl:action> at " + tag->getTagLocation());
 337                         }
 338                         else
 339                         {
 340                                 if (e->reason.empty())
 341                                 {
 342                                         std::string location = tag->getTagLocation();
 343                                         ServerInstance->SNO->WriteGlobalSno('d', "DNSBL(%s): empty reason, using defaults", location.c_str());
 344                                         e->reason = "Your IP has been blacklisted.";
 345                                 }
 346
 347                                 /* add it, all is ok */
 348                                 newentries.push_back(e);
 349                         }
 350                 }
 351
 352                 DNSBLConfEntries.swap(newentries);
 353         }
 354
 355         void OnSetUserIP(LocalUser* user) CXX11_OVERRIDE
 356         {
 357                 if ((user->exempt) || !DNS)
 358                         return;
 359
 360                 // Clients can't be in a DNSBL if they aren't connected via IPv4 or IPv6.
 361                 if (user->client_sa.family() != AF_INET && user->client_sa.family() != AF_INET6)
 362                         return;
 363
 364                 if (user->MyClass)
 365                 {
 366                         if (!user->MyClass->config->getBool("usednsbl", true))
 367                                 return;
 368                 }
 369                 else
 370                         ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "User has no connect class in OnSetUserIP");
 371
 372                 std::string reversedip;
 373                 if (user->client_sa.family() == AF_INET)
 374                 {
 375                         unsigned int a, b, c, d;
 376                         d = (unsigned int) (user->client_sa.in4.sin_addr.s_addr >> 24) & 0xFF;
 377                         c = (unsigned int) (user->client_sa.in4.sin_addr.s_addr >> 16) & 0xFF;
 378                         b = (unsigned int) (user->client_sa.in4.sin_addr.s_addr >> 8) & 0xFF;
 379                         a = (unsigned int) user->client_sa.in4.sin_addr.s_addr & 0xFF;
 380
 381                         reversedip = ConvToStr(d) + "." + ConvToStr(c) + "." + ConvToStr(b) + "." + ConvToStr(a);
 382                 }
 383                 else if (user->client_sa.family() == AF_INET6)
 384                 {
 385                         const unsigned char* ip = user->client_sa.in6.sin6_addr.s6_addr;
 386
 387                         std::string buf = BinToHex(ip, 16);
 388                         for (std::string::const_reverse_iterator it = buf.rbegin(); it != buf.rend(); ++it)
 389                         {
 390                                 reversedip.push_back(*it);
 391                                 reversedip.push_back('.');
 392                         }
 393                         reversedip.erase(reversedip.length() - 1, 1);
 394                 }
 395                 else
 396                         return;
 397
 398                 ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Reversed IP %s -> %s", user->GetIPString().c_str(), reversedip.c_str());
 399
 400                 countExt.set(user, DNSBLConfEntries.size());
 401
 402                 // For each DNSBL, we will run through this lookup
 403                 for (unsigned i = 0; i < DNSBLConfEntries.size(); ++i)
 404                 {
 405                         // Fill hostname with a dnsbl style host (d.c.b.a.domain.tld)
 406                         std::string hostname = reversedip + "." + DNSBLConfEntries[i]->domain;
 407
 408                         /* now we'd need to fire off lookups for `hostname'. */
 409                         DNSBLResolver *r = new DNSBLResolver(*this->DNS, this, nameExt, countExt, hostname, user, DNSBLConfEntries[i]);
 410                         try
 411                         {
 412                                 this->DNS->Process(r);
 413                         }
 414                         catch (DNS::Exception &ex)
 415                         {
 416                                 delete r;
 417                                 ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, ex.GetReason());
 418                         }
 419
 420                         if (user->quitting)
 421                                 break;
 422                 }
 423         }
 424
 425         ModResult OnSetConnectClass(LocalUser* user, ConnectClass* myclass) CXX11_OVERRIDE
 426         {
 427                 std::string dnsbl;
 428                 if (!myclass->config->readString("dnsbl", dnsbl))
 429                         return MOD_RES_PASSTHRU;
 430
 431                 std::string* match = nameExt.get(user);
 432                 if (!match)
 433                         return MOD_RES_PASSTHRU;
 434
 435                 if (InspIRCd::Match(*match, dnsbl))
 436                         return MOD_RES_PASSTHRU;
 437
 438                 return MOD_RES_DENY;
 439         }
 440
 441         ModResult OnCheckReady(LocalUser *user) CXX11_OVERRIDE
 442         {
 443                 if (countExt.get(user))
 444                         return MOD_RES_DENY;
 445                 return MOD_RES_PASSTHRU;
 446         }
 447
 448         ModResult OnStats(Stats::Context& stats) CXX11_OVERRIDE
 449         {
 450                 if (stats.GetSymbol() != 'd')
 451                         return MOD_RES_PASSTHRU;
 452
 453                 unsigned long total_hits = 0, total_misses = 0;
 454
 455                 for (std::vector<reference<DNSBLConfEntry> >::const_iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); ++i)
 456                 {
 457                         total_hits += (*i)->stats_hits;
 458                         total_misses += (*i)->stats_misses;
 459
 460                         stats.AddRow(304, "DNSBLSTATS DNSbl \"" + (*i)->name + "\" had " +
 461                                         ConvToStr((*i)->stats_hits) + " hits and " + ConvToStr((*i)->stats_misses) + " misses");
 462                 }
 463
 464                 stats.AddRow(304, "DNSBLSTATS Total hits: " + ConvToStr(total_hits));
 465                 stats.AddRow(304, "DNSBLSTATS Total misses: " + ConvToStr(total_misses));
 466
 467                 return MOD_RES_PASSTHRU;
 468         }
 469 };
 470
 471 MODULE_INIT(ModuleDNSBL)