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