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