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