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