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 : public refcountbase
  31 {
  32         public:
  33                 enum EnumBanaction { I_UNKNOWN, I_KILL, I_ZLINE, I_KLINE, I_GLINE, I_MARK };
  34                 enum EnumType { A_RECORD, A_BITMASK };
  35                 std::string name, ident, host, domain, reason;
  36                 EnumBanaction banaction;
  37                 EnumType type;
  38                 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                 ~DNSBLConfEntry() { }
  44 };
  45
  46
  47 /** Resolver for CGI:IRC hostnames encoded in ident/GECOS
  48  */
  49 class DNSBLResolver : public Resolver
  50 {
  51         std::string theiruid;
  52         LocalStringExt& nameExt;
  53         LocalIntExt& countExt;
  54         reference<DNSBLConfEntry> ConfEntry;
  55
  56  public:
  57
  58         DNSBLResolver(Module *me, LocalStringExt& match, LocalIntExt& ctr, const std::string &hostname, LocalUser* u, reference<DNSBLConfEntry> conf, bool &cached)
  59                 : Resolver(hostname, DNS_QUERY_A, cached, me), 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         virtual void OnLookupComplete(const std::string &result, unsigned int ttl, bool cached)
  65         {
  66                 /* Check the user still exists */
  67                 LocalUser* them = (LocalUser*)ServerInstance->FindUUID(theiruid);
  68                 if (them)
  69                 {
  70                         int i = countExt.get(them);
  71                         if (i)
  72                                 countExt.set(them, i - 1);
  73                         // All replies should be in 127.0.0.0/8
  74                         if (result.compare(0, 4, "127.") == 0)
  75                         {
  76                                 unsigned int bitmask = 0, record = 0;
  77                                 bool match = false;
  78                                 in_addr resultip;
  79
  80                                 inet_aton(result.c_str(), &resultip);
  81
  82                                 switch (ConfEntry->type)
  83                                 {
  84                                         case DNSBLConfEntry::A_BITMASK:
  85                                                 // Now we calculate the bitmask: 256*(256*(256*a+b)+c)+d
  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(), timestr.c_str(), reason.c_str());
 142                                                                 ServerInstance->XLines->ApplyLines();
 143                                                         }
 144                                                         else
 145                                                         {
 146                                                                 delete kl;
 147                                                                 return;
 148                                                         }
 149                                                         break;
 150                                                 }
 151                                                 case DNSBLConfEntry::I_GLINE:
 152                                                 {
 153                                                         GLine* gl = new GLine(ServerInstance->Time(), ConfEntry->duration, ServerInstance->Config->ServerName.c_str(), reason.c_str(),
 154                                                                         "*", them->GetIPString());
 155                                                         if (ServerInstance->XLines->AddLine(gl,NULL))
 156                                                         {
 157                                                                 std::string timestr = ServerInstance->TimeString(gl->expiry);
 158                                                                 ServerInstance->SNO->WriteGlobalSno('x',"G:line added due to DNSBL match on *@%s to expire on %s: %s",
 159                                                                         them->GetIPString(), timestr.c_str(), reason.c_str());
 160                                                                 ServerInstance->XLines->ApplyLines();
 161                                                         }
 162                                                         else
 163                                                         {
 164                                                                 delete gl;
 165                                                                 return;
 166                                                         }
 167                                                         break;
 168                                                 }
 169                                                 case DNSBLConfEntry::I_ZLINE:
 170                                                 {
 171                                                         ZLine* zl = new ZLine(ServerInstance->Time(), ConfEntry->duration, ServerInstance->Config->ServerName.c_str(), reason.c_str(),
 172                                                                         them->GetIPString());
 173                                                         if (ServerInstance->XLines->AddLine(zl,NULL))
 174                                                         {
 175                                                                 std::string timestr = ServerInstance->TimeString(zl->expiry);
 176                                                                 ServerInstance->SNO->WriteGlobalSno('x',"Z:line added due to DNSBL match on *@%s to expire on %s: %s",
 177                                                                         them->GetIPString(), timestr.c_str(), reason.c_str());
 178                                                                 ServerInstance->XLines->ApplyLines();
 179                                                         }
 180                                                         else
 181                                                         {
 182                                                                 delete zl;
 183                                                                 return;
 184                                                         }
 185                                                         break;
 186                                                 }
 187                                                 case DNSBLConfEntry::I_UNKNOWN:
 188                                                 {
 189                                                         break;
 190                                                 }
 191                                                 break;
 192                                         }
 193
 194                                         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);
 195                                 }
 196                                 else
 197                                         ConfEntry->stats_misses++;
 198                         }
 199                         else
 200                         {
 201                                 if (!result.empty())
 202                                         ServerInstance->SNO->WriteGlobalSno('a', "DNSBL: %s returned address outside of acceptable subnet 127.0.0.0/8: %s", ConfEntry->domain.c_str(), result.c_str());
 203                                 ConfEntry->stats_misses++;
 204                         }
 205                 }
 206         }
 207
 208         virtual void OnError(ResolverError e, const std::string &errormessage)
 209         {
 210                 LocalUser* them = (LocalUser*)ServerInstance->FindUUID(theiruid);
 211                 if (them)
 212                 {
 213                         int i = countExt.get(them);
 214                         if (i)
 215                                 countExt.set(them, i - 1);
 216                 }
 217         }
 218
 219         virtual ~DNSBLResolver()
 220         {
 221         }
 222 };
 223
 224 class ModuleDNSBL : public Module
 225 {
 226         std::vector<reference<DNSBLConfEntry> > DNSBLConfEntries;
 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() : nameExt("dnsbl_match", this), countExt("dnsbl_pending", this) { }
 250
 251         void init()
 252         {
 253                 ReadConf();
 254                 ServerInstance->Modules->AddService(nameExt);
 255                 ServerInstance->Modules->AddService(countExt);
 256                 Implementation eventlist[] = { I_OnRehash, I_OnSetUserIP, I_OnStats, I_OnSetConnectClass, I_OnCheckReady };
 257                 ServerInstance->Modules->Attach(eventlist, this, sizeof(eventlist)/sizeof(Implementation));
 258         }
 259
 260         Version GetVersion()
 261         {
 262                 return Version("Provides handling of DNS blacklists", VF_VENDOR);
 263         }
 264
 265         /** Fill our conf vector with data
 266          */
 267         void ReadConf()
 268         {
 269                 DNSBLConfEntries.clear();
 270
 271                 ConfigTagList dnsbls = ServerInstance->Config->ConfTags("dnsbl");
 272                 for(ConfigIter i = dnsbls.first; i != dnsbls.second; ++i)
 273                 {
 274                         ConfigTag* tag = i->second;
 275                         reference<DNSBLConfEntry> e = new DNSBLConfEntry();
 276
 277                         e->name = tag->getString("name");
 278                         e->ident = tag->getString("ident");
 279                         e->host = tag->getString("host");
 280                         e->reason = tag->getString("reason");
 281                         e->domain = tag->getString("domain");
 282
 283                         if (tag->getString("type") == "bitmask")
 284                         {
 285                                 e->type = DNSBLConfEntry::A_BITMASK;
 286                                 e->bitmask = tag->getInt("bitmask");
 287                         }
 288                         else
 289                         {
 290                                 memset(e->records, 0, sizeof(e->records));
 291                                 e->type = DNSBLConfEntry::A_RECORD;
 292                                 irc::portparser portrange(tag->getString("records"), false);
 293                                 long item = -1;
 294                                 while ((item = portrange.GetToken()))
 295                                         e->records[item] = 1;
 296                         }
 297
 298                         e->banaction = str2banaction(tag->getString("action"));
 299                         e->duration = ServerInstance->Duration(tag->getString("duration", "60"));
 300
 301                         /* Use portparser for record replies */
 302
 303                         /* yeah, logic here is a little messy */
 304                         if ((e->bitmask <= 0) && (DNSBLConfEntry::A_BITMASK == e->type))
 305                         {
 306                                 std::string location = tag->getTagLocation();
 307                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(%s): invalid bitmask", location.c_str());
 308                         }
 309                         else if (e->name.empty())
 310                         {
 311                                 std::string location = tag->getTagLocation();
 312                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(%s): Invalid name", location.c_str());
 313                         }
 314                         else if (e->domain.empty())
 315                         {
 316                                 std::string location = tag->getTagLocation();
 317                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(%s): Invalid domain", location.c_str());
 318                         }
 319                         else if (e->banaction == DNSBLConfEntry::I_UNKNOWN)
 320                         {
 321                                 std::string location = tag->getTagLocation();
 322                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(%s): Invalid banaction", location.c_str());
 323                         }
 324                         else if (e->duration <= 0)
 325                         {
 326                                 std::string location = tag->getTagLocation();
 327                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(%s): Invalid duration", location.c_str());
 328                         }
 329                         else
 330                         {
 331                                 if (e->reason.empty())
 332                                 {
 333                                         std::string location = tag->getTagLocation();
 334                                         ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(%s): empty reason, using defaults", location.c_str());
 335                                         e->reason = "Your IP has been blacklisted.";
 336                                 }
 337
 338                                 /* add it, all is ok */
 339                                 DNSBLConfEntries.push_back(e);
 340                         }
 341                 }
 342         }
 343
 344         void OnRehash(User* user)
 345         {
 346                 ReadConf();
 347         }
 348
 349         void OnSetUserIP(LocalUser* user)
 350         {
 351                 if ((user->exempt) || (user->client_sa.sa.sa_family != AF_INET))
 352                         return;
 353
 354                 if (user->MyClass)
 355                 {
 356                         if (!user->MyClass->config->getBool("usednsbl", true))
 357                                 return;
 358                 }
 359                 else
 360                         ServerInstance->Logs->Log("m_dnsbl", DEBUG, "User has no connect class in OnSetUserIP");
 361
 362                 unsigned char a, b, c, d;
 363                 char reversedipbuf[128];
 364                 std::string reversedip;
 365
 366                 d = (unsigned char) (user->client_sa.in4.sin_addr.s_addr >> 24) & 0xFF;
 367                 c = (unsigned char) (user->client_sa.in4.sin_addr.s_addr >> 16) & 0xFF;
 368                 b = (unsigned char) (user->client_sa.in4.sin_addr.s_addr >> 8) & 0xFF;
 369                 a = (unsigned char) user->client_sa.in4.sin_addr.s_addr & 0xFF;
 370
 371                 snprintf(reversedipbuf, 128, "%d.%d.%d.%d", d, c, b, a);
 372                 reversedip = std::string(reversedipbuf);
 373
 374                 countExt.set(user, DNSBLConfEntries.size());
 375
 376                 // For each DNSBL, we will run through this lookup
 377                 unsigned int i = 0;
 378                 while (i < DNSBLConfEntries.size())
 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                         bool cached;
 385                         DNSBLResolver *r = new DNSBLResolver(this, nameExt, countExt, hostname, user, DNSBLConfEntries[i], cached);
 386                         ServerInstance->AddResolver(r, cached);
 387                         if (user->quitting)
 388                                 break;
 389                         i++;
 390                 }
 391         }
 392
 393         ModResult OnSetConnectClass(LocalUser* user, ConnectClass* myclass)
 394         {
 395                 std::string dnsbl;
 396                 if (!myclass->config->readString("dnsbl", dnsbl))
 397                         return MOD_RES_PASSTHRU;
 398                 std::string* match = nameExt.get(user);
 399                 std::string myname = match ? *match : "";
 400                 if (dnsbl == myname)
 401                         return MOD_RES_PASSTHRU;
 402                 return MOD_RES_DENY;
 403         }
 404
 405         ModResult OnCheckReady(LocalUser *user)
 406         {
 407                 if (countExt.get(user))
 408                         return MOD_RES_DENY;
 409                 return MOD_RES_PASSTHRU;
 410         }
 411
 412         ModResult OnStats(char symbol, User* user, string_list &results)
 413         {
 414                 if (symbol != 'd')
 415                         return MOD_RES_PASSTHRU;
 416
 417                 unsigned long total_hits = 0, total_misses = 0;
 418
 419                 for (std::vector<reference<DNSBLConfEntry> >::const_iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); ++i)
 420                 {
 421                         total_hits += (*i)->stats_hits;
 422                         total_misses += (*i)->stats_misses;
 423
 424                         results.push_back(ServerInstance->Config->ServerName + " 304 " + user->nick + " :DNSBLSTATS DNSbl \"" + (*i)->name + "\" had " +
 425                                         ConvToStr((*i)->stats_hits) + " hits and " + ConvToStr((*i)->stats_misses) + " misses");
 426                 }
 427
 428                 results.push_back(ServerInstance->Config->ServerName + " 304 " + user->nick + " :DNSBLSTATS Total hits: " + ConvToStr(total_hits));
 429                 results.push_back(ServerInstance->Config->ServerName + " 304 " + user->nick + " :DNSBLSTATS Total misses: " + ConvToStr(total_misses));
 430
 431                 return MOD_RES_PASSTHRU;
 432         }
 433 };
 434
 435 MODULE_INIT(ModuleDNSBL)