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
  26 /* $ModDesc: Provides handling of DNS blacklists */
  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                 ~DNSBLConfEntry() { }
  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(), 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(), 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(), 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         virtual ~DNSBLResolver()
 205         {
 206         }
 207 };
 208
 209 class ModuleDNSBL : public Module
 210 {
 211         std::vector<DNSBLConfEntry *> DNSBLConfEntries;
 212         LocalStringExt nameExt;
 213         LocalIntExt countExt;
 214
 215         /*
 216          *      Convert a string to EnumBanaction
 217          */
 218         DNSBLConfEntry::EnumBanaction str2banaction(const std::string &action)
 219         {
 220                 if(action.compare("KILL")==0)
 221                         return DNSBLConfEntry::I_KILL;
 222                 if(action.compare("KLINE")==0)
 223                         return DNSBLConfEntry::I_KLINE;
 224                 if(action.compare("ZLINE")==0)
 225                         return DNSBLConfEntry::I_ZLINE;
 226                 if(action.compare("GLINE")==0)
 227                         return DNSBLConfEntry::I_GLINE;
 228                 if(action.compare("MARK")==0)
 229                         return DNSBLConfEntry::I_MARK;
 230
 231                 return DNSBLConfEntry::I_UNKNOWN;
 232         }
 233  public:
 234         ModuleDNSBL() : nameExt("dnsbl_match", this), countExt("dnsbl_pending", this) { }
 235
 236         void init()
 237         {
 238                 ReadConf();
 239                 ServerInstance->Modules->AddService(nameExt);
 240                 ServerInstance->Modules->AddService(countExt);
 241                 Implementation eventlist[] = { I_OnRehash, I_OnSetUserIP, I_OnStats, I_OnSetConnectClass, I_OnCheckReady };
 242                 ServerInstance->Modules->Attach(eventlist, this, 5);
 243         }
 244
 245         virtual ~ModuleDNSBL()
 246         {
 247                 ClearEntries();
 248         }
 249
 250         Version GetVersion()
 251         {
 252                 return Version("Provides handling of DNS blacklists", VF_VENDOR);
 253         }
 254
 255         /** Clear entries and free the mem it was using
 256          */
 257         void ClearEntries()
 258         {
 259                 for (std::vector<DNSBLConfEntry *>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 260                         delete *i;
 261                 DNSBLConfEntries.clear();
 262         }
 263
 264         /** Fill our conf vector with data
 265          */
 266         void ReadConf()
 267         {
 268                 ClearEntries();
 269
 270                 ConfigTagList dnsbls = ServerInstance->Config->ConfTags("dnsbl");
 271                 for(ConfigIter i = dnsbls.first; i != dnsbls.second; ++i)
 272                 {
 273                         ConfigTag* tag = i->second;
 274                         DNSBLConfEntry *e = new DNSBLConfEntry();
 275
 276                         e->name = tag->getString("name");
 277                         e->ident = tag->getString("ident");
 278                         e->host = tag->getString("host");
 279                         e->reason = tag->getString("reason");
 280                         e->domain = tag->getString("domain");
 281
 282                         if (tag->getString("type") == "bitmask")
 283                         {
 284                                 e->type = DNSBLConfEntry::A_BITMASK;
 285                                 e->bitmask = tag->getInt("bitmask");
 286                         }
 287                         else
 288                         {
 289                                 memset(e->records, 0, sizeof(e->records));
 290                                 e->type = DNSBLConfEntry::A_RECORD;
 291                                 irc::portparser portrange(tag->getString("records"), false);
 292                                 long item = -1;
 293                                 while ((item = portrange.GetToken()))
 294                                         e->records[item] = 1;
 295                         }
 296
 297                         e->banaction = str2banaction(tag->getString("action"));
 298                         e->duration = ServerInstance->Duration(tag->getString("duration", "60"));
 299
 300                         /* Use portparser for record replies */
 301
 302                         /* yeah, logic here is a little messy */
 303                         if ((e->bitmask <= 0) && (DNSBLConfEntry::A_BITMASK == e->type))
 304                         {
 305                                 std::string location = tag->getTagLocation();
 306                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(%s): invalid bitmask", location.c_str());
 307                         }
 308                         else if (e->name.empty())
 309                         {
 310                                 std::string location = tag->getTagLocation();
 311                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(%s): Invalid name", location.c_str());
 312                         }
 313                         else if (e->domain.empty())
 314                         {
 315                                 std::string location = tag->getTagLocation();
 316                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(%s): Invalid domain", location.c_str());
 317                         }
 318                         else if (e->banaction == DNSBLConfEntry::I_UNKNOWN)
 319                         {
 320                                 std::string location = tag->getTagLocation();
 321                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(%s): Invalid banaction", location.c_str());
 322                         }
 323                         else if (e->duration <= 0)
 324                         {
 325                                 std::string location = tag->getTagLocation();
 326                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(%s): Invalid duration", location.c_str());
 327                         }
 328                         else
 329                         {
 330                                 if (e->reason.empty())
 331                                 {
 332                                         std::string location = tag->getTagLocation();
 333                                         ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(%s): empty reason, using defaults", location.c_str());
 334                                         e->reason = "Your IP has been blacklisted.";
 335                                 }
 336
 337                                 /* add it, all is ok */
 338                                 DNSBLConfEntries.push_back(e);
 339                                 continue;
 340                         }
 341
 342                         /* delete and drop it, error somewhere */
 343                         delete e;
 344                 }
 345         }
 346
 347         void OnRehash(User* user)
 348         {
 349                 ReadConf();
 350         }
 351
 352         void OnSetUserIP(LocalUser* user)
 353         {
 354                 if (user->exempt)
 355                         return;
 356
 357                 unsigned char a, b, c, d;
 358                 char reversedipbuf[128];
 359                 std::string reversedip;
 360
 361                 if (user->client_sa.sa.sa_family != AF_INET)
 362                         return;
 363
 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                 snprintf(reversedipbuf, 128, "%d.%d.%d.%d", d, c, b, a);
 370                 reversedip = std::string(reversedipbuf);
 371
 372                 // For each DNSBL, we will run through this lookup
 373                 unsigned int i = 0;
 374                 while (i < DNSBLConfEntries.size())
 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                         bool cached;
 381                         DNSBLResolver *r = new DNSBLResolver(this, nameExt, countExt, hostname, user, DNSBLConfEntries[i], cached);
 382                         ServerInstance->AddResolver(r, cached);
 383                         i++;
 384                 }
 385                 countExt.set(user, i);
 386         }
 387
 388         ModResult OnSetConnectClass(LocalUser* user, ConnectClass* myclass)
 389         {
 390                 std::string dnsbl;
 391                 if (!myclass->config->readString("dnsbl", dnsbl))
 392                         return MOD_RES_PASSTHRU;
 393                 std::string* match = nameExt.get(user);
 394                 std::string myname = match ? *match : "";
 395                 if (dnsbl == myname)
 396                         return MOD_RES_PASSTHRU;
 397                 return MOD_RES_DENY;
 398         }
 399
 400         ModResult OnCheckReady(LocalUser *user)
 401         {
 402                 if (countExt.get(user))
 403                         return MOD_RES_DENY;
 404                 return MOD_RES_PASSTHRU;
 405         }
 406
 407         ModResult OnStats(char symbol, User* user, string_list &results)
 408         {
 409                 if (symbol != 'd')
 410                         return MOD_RES_PASSTHRU;
 411
 412                 unsigned long total_hits = 0, total_misses = 0;
 413
 414                 for (std::vector<DNSBLConfEntry*>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 415                 {
 416                         total_hits += (*i)->stats_hits;
 417                         total_misses += (*i)->stats_misses;
 418
 419                         results.push_back(std::string(ServerInstance->Config->ServerName.c_str()) + " 304 " + user->nick + " :DNSBLSTATS DNSbl \"" + (*i)->name + "\" had " +
 420                                         ConvToStr((*i)->stats_hits) + " hits and " + ConvToStr((*i)->stats_misses) + " misses");
 421                 }
 422
 423                 results.push_back(std::string(ServerInstance->Config->ServerName.c_str()) + " 304 " + user->nick + " :DNSBLSTATS Total hits: " + ConvToStr(total_hits));
 424                 results.push_back(std::string(ServerInstance->Config->ServerName.c_str()) + " 304 " + user->nick + " :DNSBLSTATS Total misses: " + ConvToStr(total_misses));
 425
 426                 return MOD_RES_PASSTHRU;
 427         }
 428 };
 429
 430 MODULE_INIT(ModuleDNSBL)