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
  27 /* $ModDesc: Provides handling of DNS blacklists */
  28
  29 /* Class holding data for a single entry */
  30 class DNSBLConfEntry
  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                 long duration;
  39                 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/GECOS
  47  */
  48 class DNSBLResolver : public Resolver
  49 {
  50         std::string theiruid;
  51         LocalStringExt& nameExt;
  52         LocalIntExt& countExt;
  53         DNSBLConfEntry *ConfEntry;
  54
  55  public:
  56
  57         DNSBLResolver(Module *me, LocalStringExt& match, LocalIntExt& ctr, const std::string &hostname, LocalUser* u, DNSBLConfEntry *conf, bool &cached)
  58                 : Resolver(hostname, DNS_QUERY_A, cached, me), 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         virtual void OnLookupComplete(const std::string &result, unsigned int ttl, bool cached)
  64         {
  65                 /* Check the user still exists */
  66                 LocalUser* them = (LocalUser*)ServerInstance->FindUUID(theiruid);
  67                 if (them)
  68                 {
  69                         int i = countExt.get(them);
  70                         if (i)
  71                                 countExt.set(them, i - 1);
  72                         // Now we calculate the bitmask: 256*(256*(256*a+b)+c)+d
  73                         if(result.length())
  74                         {
  75                                 unsigned int bitmask = 0, record = 0;
  76                                 bool match = false;
  77                                 in_addr resultip;
  78
  79                                 inet_aton(result.c_str(), &resultip);
  80
  81                                 switch (ConfEntry->type)
  82                                 {
  83                                         case DNSBLConfEntry::A_BITMASK:
  84                                                 bitmask = resultip.s_addr >> 24; /* Last octet (network byte order) */
  85                                                 bitmask &= ConfEntry->bitmask;
  86                                                 match = (bitmask != 0);
  87                                         break;
  88                                         case DNSBLConfEntry::A_RECORD:
  89                                                 record = resultip.s_addr >> 24; /* Last octet */
  90                                                 match = (ConfEntry->records[record] == 1);
  91                                         break;
  92                                 }
  93
  94                                 if (match)
  95                                 {
  96                                         std::string reason = ConfEntry->reason;
  97                                         std::string::size_type x = reason.find("%ip%");
  98                                         while (x != std::string::npos)
  99                                         {
 100                                                 reason.erase(x, 4);
 101                                                 reason.insert(x, them->GetIPString());
 102                                                 x = reason.find("%ip%");
 103                                         }
 104
 105                                         ConfEntry->stats_hits++;
 106
 107                                         switch (ConfEntry->banaction)
 108                                         {
 109                                                 case DNSBLConfEntry::I_KILL:
 110                                                 {
 111                                                         ServerInstance->Users->QuitUser(them, "Killed (" + reason + ")");
 112                                                         break;
 113                                                 }
 114                                                 case DNSBLConfEntry::I_MARK:
 115                                                 {
 116                                                         if (!ConfEntry->ident.empty())
 117                                                         {
 118                                                                 them->WriteServ("304 " + them->nick + " :Your ident has been set to " + ConfEntry->ident + " because you matched " + reason);
 119                                                                 them->ChangeIdent(ConfEntry->ident.c_str());
 120                                                         }
 121
 122                                                         if (!ConfEntry->host.empty())
 123                                                         {
 124                                                                 them->WriteServ("304 " + them->nick + " :Your host has been set to " + ConfEntry->host + " because you matched " + reason);
 125                                                                 them->ChangeDisplayedHost(ConfEntry->host.c_str());
 126                                                         }
 127
 128                                                         nameExt.set(them, ConfEntry->name);
 129                                                         break;
 130                                                 }
 131                                                 case DNSBLConfEntry::I_KLINE:
 132                                                 {
 133                                                         KLine* kl = new KLine(ServerInstance->Time(), ConfEntry->duration, ServerInstance->Config->ServerName.c_str(), reason.c_str(),
 134                                                                         "*", them->GetIPString());
 135                                                         if (ServerInstance->XLines->AddLine(kl,NULL))
 136                                                         {
 137                                                                 std::string timestr = ServerInstance->TimeString(kl->expiry);
 138                                                                 ServerInstance->SNO->WriteGlobalSno('x',"K:line added due to DNSBL match on *@%s to expire on %s: %s",
 139                                                                         them->GetIPString().c_str(), timestr.c_str(), reason.c_str());
 140                                                                 ServerInstance->XLines->ApplyLines();
 141                                                         }
 142                                                         else
 143                                                                 delete kl;
 144                                                         break;
 145                                                 }
 146                                                 case DNSBLConfEntry::I_GLINE:
 147                                                 {
 148                                                         GLine* gl = new GLine(ServerInstance->Time(), ConfEntry->duration, ServerInstance->Config->ServerName.c_str(), reason.c_str(),
 149                                                                         "*", them->GetIPString());
 150                                                         if (ServerInstance->XLines->AddLine(gl,NULL))
 151                                                         {
 152                                                                 std::string timestr = ServerInstance->TimeString(gl->expiry);
 153                                                                 ServerInstance->SNO->WriteGlobalSno('x',"G:line added due to DNSBL match on *@%s to expire on %s: %s",
 154                                                                         them->GetIPString().c_str(), timestr.c_str(), reason.c_str());
 155                                                                 ServerInstance->XLines->ApplyLines();
 156                                                         }
 157                                                         else
 158                                                                 delete gl;
 159                                                         break;
 160                                                 }
 161                                                 case DNSBLConfEntry::I_ZLINE:
 162                                                 {
 163                                                         ZLine* zl = new ZLine(ServerInstance->Time(), ConfEntry->duration, ServerInstance->Config->ServerName.c_str(), reason.c_str(),
 164                                                                         them->GetIPString());
 165                                                         if (ServerInstance->XLines->AddLine(zl,NULL))
 166                                                         {
 167                                                                 std::string timestr = ServerInstance->TimeString(zl->expiry);
 168                                                                 ServerInstance->SNO->WriteGlobalSno('x',"Z: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                                                                 delete zl;
 174                                                         break;
 175                                                 }
 176                                                 case DNSBLConfEntry::I_UNKNOWN:
 177                                                 {
 178                                                         break;
 179                                                 }
 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                         else
 189                                 ConfEntry->stats_misses++;
 190                 }
 191         }
 192
 193         virtual void OnError(ResolverError e, const std::string &errormessage)
 194         {
 195                 LocalUser* them = (LocalUser*)ServerInstance->FindUUID(theiruid);
 196                 if (them)
 197                 {
 198                         int i = countExt.get(them);
 199                         if (i)
 200                                 countExt.set(them, i - 1);
 201                 }
 202         }
 203 };
 204
 205 class ModuleDNSBL : public Module
 206 {
 207         std::vector<DNSBLConfEntry *> DNSBLConfEntries;
 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() : nameExt("dnsbl_match", this), countExt("dnsbl_pending", this) { }
 231
 232         void init()
 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         virtual ~ModuleDNSBL()
 242         {
 243                 ClearEntries();
 244         }
 245
 246         Version GetVersion()
 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)
 344         {
 345                 ReadConf();
 346         }
 347
 348         void OnSetUserIP(LocalUser* user)
 349         {
 350                 if ((user->exempt) || (user->client_sa.sa.sa_family != AF_INET))
 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                 char reversedipbuf[128];
 363                 std::string reversedip;
 364
 365                 d = (unsigned char) (user->client_sa.in4.sin_addr.s_addr >> 24) & 0xFF;
 366                 c = (unsigned char) (user->client_sa.in4.sin_addr.s_addr >> 16) & 0xFF;
 367                 b = (unsigned char) (user->client_sa.in4.sin_addr.s_addr >> 8) & 0xFF;
 368                 a = (unsigned char) user->client_sa.in4.sin_addr.s_addr & 0xFF;
 369
 370                 snprintf(reversedipbuf, 128, "%d.%d.%d.%d", d, c, b, a);
 371                 reversedip = std::string(reversedipbuf);
 372
 373                 countExt.set(user, DNSBLConfEntries.size());
 374
 375                 // For each DNSBL, we will run through this lookup
 376                 unsigned int i = 0;
 377                 while (i < DNSBLConfEntries.size())
 378                 {
 379                         // Fill hostname with a dnsbl style host (d.c.b.a.domain.tld)
 380                         std::string hostname = reversedip + "." + DNSBLConfEntries[i]->domain;
 381
 382                         /* now we'd need to fire off lookups for `hostname'. */
 383                         bool cached;
 384                         DNSBLResolver *r = new DNSBLResolver(this, nameExt, countExt, hostname, user, DNSBLConfEntries[i], cached);
 385                         ServerInstance->AddResolver(r, cached);
 386                         if (user->quitting)
 387                                 break;
 388                         i++;
 389                 }
 390         }
 391
 392         ModResult OnSetConnectClass(LocalUser* user, ConnectClass* myclass)
 393         {
 394                 std::string dnsbl;
 395                 if (!myclass->config->readString("dnsbl", dnsbl))
 396                         return MOD_RES_PASSTHRU;
 397                 std::string* match = nameExt.get(user);
 398                 std::string myname = match ? *match : "";
 399                 if (dnsbl == myname)
 400                         return MOD_RES_PASSTHRU;
 401                 return MOD_RES_DENY;
 402         }
 403
 404         ModResult OnCheckReady(LocalUser *user)
 405         {
 406                 if (countExt.get(user))
 407                         return MOD_RES_DENY;
 408                 return MOD_RES_PASSTHRU;
 409         }
 410
 411         ModResult OnStats(char symbol, User* user, string_list &results)
 412         {
 413                 if (symbol != 'd')
 414                         return MOD_RES_PASSTHRU;
 415
 416                 unsigned long total_hits = 0, total_misses = 0;
 417
 418                 for (std::vector<DNSBLConfEntry*>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 419                 {
 420                         total_hits += (*i)->stats_hits;
 421                         total_misses += (*i)->stats_misses;
 422
 423                         results.push_back(ServerInstance->Config->ServerName + " 304 " + user->nick + " :DNSBLSTATS DNSbl \"" + (*i)->name + "\" had " +
 424                                         ConvToStr((*i)->stats_hits) + " hits and " + ConvToStr((*i)->stats_misses) + " misses");
 425                 }
 426
 427                 results.push_back(ServerInstance->Config->ServerName + " 304 " + user->nick + " :DNSBLSTATS Total hits: " + ConvToStr(total_hits));
 428                 results.push_back(ServerInstance->Config->ServerName + " 304 " + user->nick + " :DNSBLSTATS Total misses: " + ConvToStr(total_misses));
 429
 430                 return MOD_RES_PASSTHRU;
 431         }
 432 };
 433
 434 MODULE_INIT(ModuleDNSBL)