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 #ifndef WINDOWS
  28 #include <sys/types.h>
  29 #include <sys/socket.h>
  30 #include <netinet/in.h>
  31 #include <arpa/inet.h>
  32 #endif
  33
  34 /* $ModDesc: Provides handling of DNS blacklists */
  35
  36 /* Class holding data for a single entry */
  37 class DNSBLConfEntry
  38 {
  39         public:
  40                 enum EnumBanaction { I_UNKNOWN, I_KILL, I_ZLINE, I_KLINE, I_GLINE, I_MARK };
  41                 enum EnumType { A_RECORD, A_BITMASK };
  42                 std::string name, ident, host, domain, reason;
  43                 EnumBanaction banaction;
  44                 EnumType type;
  45                 long duration;
  46                 int bitmask;
  47                 unsigned char records[256];
  48                 unsigned long stats_hits, stats_misses;
  49                 DNSBLConfEntry(): type(A_BITMASK),duration(86400),bitmask(0),stats_hits(0), stats_misses(0) {}
  50                 ~DNSBLConfEntry() { }
  51 };
  52
  53
  54 /** Resolver for CGI:IRC hostnames encoded in ident/GECOS
  55  */
  56 class DNSBLResolver : public Resolver
  57 {
  58         std::string theiruid;
  59         LocalStringExt& nameExt;
  60         LocalIntExt& countExt;
  61         DNSBLConfEntry *ConfEntry;
  62
  63  public:
  64
  65         DNSBLResolver(Module *me, LocalStringExt& match, LocalIntExt& ctr, const std::string &hostname, LocalUser* u, DNSBLConfEntry *conf, bool &cached)
  66                 : Resolver(hostname, DNS_QUERY_A, cached, me), theiruid(u->uuid), nameExt(match), countExt(ctr), ConfEntry(conf)
  67         {
  68         }
  69
  70         /* Note: This may be called multiple times for multiple A record results */
  71         virtual void OnLookupComplete(const std::string &result, unsigned int ttl, bool cached)
  72         {
  73                 /* Check the user still exists */
  74                 LocalUser* them = (LocalUser*)ServerInstance->FindUUID(theiruid);
  75                 if (them)
  76                 {
  77                         int i = countExt.get(them);
  78                         if (i)
  79                                 countExt.set(them, i - 1);
  80                         // Now we calculate the bitmask: 256*(256*(256*a+b)+c)+d
  81                         if(result.length())
  82                         {
  83                                 unsigned int bitmask = 0, record = 0;
  84                                 bool match = false;
  85                                 in_addr resultip;
  86
  87                                 inet_aton(result.c_str(), &resultip);
  88
  89                                 switch (ConfEntry->type)
  90                                 {
  91                                         case DNSBLConfEntry::A_BITMASK:
  92                                                 bitmask = resultip.s_addr >> 24; /* Last octet (network byte order) */
  93                                                 bitmask &= ConfEntry->bitmask;
  94                                                 match = (bitmask != 0);
  95                                         break;
  96                                         case DNSBLConfEntry::A_RECORD:
  97                                                 record = resultip.s_addr >> 24; /* Last octet */
  98                                                 match = (ConfEntry->records[record] == 1);
  99                                         break;
 100                                 }
 101
 102                                 if (match)
 103                                 {
 104                                         std::string reason = ConfEntry->reason;
 105                                         std::string::size_type x = reason.find("%ip%");
 106                                         while (x != std::string::npos)
 107                                         {
 108                                                 reason.erase(x, 4);
 109                                                 reason.insert(x, them->GetIPString());
 110                                                 x = reason.find("%ip%");
 111                                         }
 112
 113                                         ConfEntry->stats_hits++;
 114
 115                                         switch (ConfEntry->banaction)
 116                                         {
 117                                                 case DNSBLConfEntry::I_KILL:
 118                                                 {
 119                                                         ServerInstance->Users->QuitUser(them, std::string("Killed (") + reason + ")");
 120                                                         break;
 121                                                 }
 122                                                 case DNSBLConfEntry::I_MARK:
 123                                                 {
 124                                                         if (!ConfEntry->ident.empty())
 125                                                         {
 126                                                                 them->WriteServ("304 " + them->nick + " :Your ident has been set to " + ConfEntry->ident + " because you matched " + reason);
 127                                                                 them->ChangeIdent(ConfEntry->ident.c_str());
 128                                                         }
 129
 130                                                         if (!ConfEntry->host.empty())
 131                                                         {
 132                                                                 them->WriteServ("304 " + them->nick + " :Your host has been set to " + ConfEntry->host + " because you matched " + reason);
 133                                                                 them->ChangeDisplayedHost(ConfEntry->host.c_str());
 134                                                         }
 135
 136                                                         nameExt.set(them, ConfEntry->name);
 137                                                         break;
 138                                                 }
 139                                                 case DNSBLConfEntry::I_KLINE:
 140                                                 {
 141                                                         KLine* kl = new KLine(ServerInstance->Time(), ConfEntry->duration, ServerInstance->Config->ServerName.c_str(), reason.c_str(),
 142                                                                         "*", them->GetIPString());
 143                                                         if (ServerInstance->XLines->AddLine(kl,NULL))
 144                                                         {
 145                                                                 ServerInstance->SNO->WriteGlobalSno('x',"K:line added due to DNSBL match on *@%s to expire on %s: %s",
 146                                                                         them->GetIPString(), ServerInstance->TimeString(kl->expiry).c_str(), reason.c_str());
 147                                                                 ServerInstance->XLines->ApplyLines();
 148                                                         }
 149                                                         else
 150                                                                 delete kl;
 151                                                         break;
 152                                                 }
 153                                                 case DNSBLConfEntry::I_GLINE:
 154                                                 {
 155                                                         GLine* gl = new GLine(ServerInstance->Time(), ConfEntry->duration, ServerInstance->Config->ServerName.c_str(), reason.c_str(),
 156                                                                         "*", them->GetIPString());
 157                                                         if (ServerInstance->XLines->AddLine(gl,NULL))
 158                                                         {
 159                                                                 ServerInstance->SNO->WriteGlobalSno('x',"G:line added due to DNSBL match on *@%s to expire on %s: %s",
 160                                                                         them->GetIPString(), ServerInstance->TimeString(gl->expiry).c_str(), reason.c_str());
 161                                                                 ServerInstance->XLines->ApplyLines();
 162                                                         }
 163                                                         else
 164                                                                 delete gl;
 165                                                         break;
 166                                                 }
 167                                                 case DNSBLConfEntry::I_ZLINE:
 168                                                 {
 169                                                         ZLine* zl = new ZLine(ServerInstance->Time(), ConfEntry->duration, ServerInstance->Config->ServerName.c_str(), reason.c_str(),
 170                                                                         them->GetIPString());
 171                                                         if (ServerInstance->XLines->AddLine(zl,NULL))
 172                                                         {
 173                                                                 ServerInstance->SNO->WriteGlobalSno('x',"Z:line added due to DNSBL match on *@%s to expire on %s: %s",
 174                                                                         them->GetIPString(), ServerInstance->TimeString(zl->expiry).c_str(), reason.c_str());
 175                                                                 ServerInstance->XLines->ApplyLines();
 176                                                         }
 177                                                         else
 178                                                                 delete zl;
 179                                                         break;
 180                                                 }
 181                                                 case DNSBLConfEntry::I_UNKNOWN:
 182                                                 {
 183                                                         break;
 184                                                 }
 185                                                 break;
 186                                         }
 187
 188                                         ServerInstance->SNO->WriteGlobalSno('a', "Connecting user %s detected as being on a DNS blacklist (%s) with result %d", them->GetFullRealHost().c_str(), ConfEntry->domain.c_str(), (ConfEntry->type==DNSBLConfEntry::A_BITMASK) ? bitmask : record);
 189                                 }
 190                                 else
 191                                         ConfEntry->stats_misses++;
 192                         }
 193                         else
 194                                 ConfEntry->stats_misses++;
 195                 }
 196         }
 197
 198         virtual void OnError(ResolverError e, const std::string &errormessage)
 199         {
 200                 LocalUser* them = (LocalUser*)ServerInstance->FindUUID(theiruid);
 201                 if (them)
 202                 {
 203                         int i = countExt.get(them);
 204                         if (i)
 205                                 countExt.set(them, i - 1);
 206                 }
 207         }
 208
 209         virtual ~DNSBLResolver()
 210         {
 211         }
 212 };
 213
 214 class ModuleDNSBL : public Module
 215 {
 216         std::vector<DNSBLConfEntry *> DNSBLConfEntries;
 217         LocalStringExt nameExt;
 218         LocalIntExt countExt;
 219
 220         /*
 221          *      Convert a string to EnumBanaction
 222          */
 223         DNSBLConfEntry::EnumBanaction str2banaction(const std::string &action)
 224         {
 225                 if(action.compare("KILL")==0)
 226                         return DNSBLConfEntry::I_KILL;
 227                 if(action.compare("KLINE")==0)
 228                         return DNSBLConfEntry::I_KLINE;
 229                 if(action.compare("ZLINE")==0)
 230                         return DNSBLConfEntry::I_ZLINE;
 231                 if(action.compare("GLINE")==0)
 232                         return DNSBLConfEntry::I_GLINE;
 233                 if(action.compare("MARK")==0)
 234                         return DNSBLConfEntry::I_MARK;
 235
 236                 return DNSBLConfEntry::I_UNKNOWN;
 237         }
 238  public:
 239         ModuleDNSBL() : nameExt("dnsbl_match", this), countExt("dnsbl_pending", this) { }
 240
 241         void init()
 242         {
 243                 ReadConf();
 244                 ServerInstance->Modules->AddService(nameExt);
 245                 ServerInstance->Modules->AddService(countExt);
 246                 Implementation eventlist[] = { I_OnRehash, I_OnUserInit, I_OnStats, I_OnSetConnectClass, I_OnCheckReady };
 247                 ServerInstance->Modules->Attach(eventlist, this, 5);
 248         }
 249
 250         virtual ~ModuleDNSBL()
 251         {
 252                 ClearEntries();
 253         }
 254
 255         Version GetVersion()
 256         {
 257                 return Version("Provides handling of DNS blacklists", VF_VENDOR);
 258         }
 259
 260         /** Clear entries and free the mem it was using
 261          */
 262         void ClearEntries()
 263         {
 264                 for (std::vector<DNSBLConfEntry *>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 265                         delete *i;
 266                 DNSBLConfEntries.clear();
 267         }
 268
 269         /** Fill our conf vector with data
 270          */
 271         void ReadConf()
 272         {
 273                 ClearEntries();
 274
 275                 ConfigTagList dnsbls = ServerInstance->Config->ConfTags("dnsbl");
 276                 for(ConfigIter i = dnsbls.first; i != dnsbls.second; ++i)
 277                 {
 278                         ConfigTag* tag = i->second;
 279                         DNSBLConfEntry *e = new DNSBLConfEntry();
 280
 281                         e->name = tag->getString("name");
 282                         e->ident = tag->getString("ident");
 283                         e->host = tag->getString("host");
 284                         e->reason = tag->getString("reason");
 285                         e->domain = tag->getString("domain");
 286
 287                         if (tag->getString("type") == "bitmask")
 288                         {
 289                                 e->type = DNSBLConfEntry::A_BITMASK;
 290                                 e->bitmask = tag->getInt("bitmask");
 291                         }
 292                         else
 293                         {
 294                                 memset(e->records, 0, sizeof(e->records));
 295                                 e->type = DNSBLConfEntry::A_RECORD;
 296                                 irc::portparser portrange(tag->getString("records"), false);
 297                                 long item = -1;
 298                                 while ((item = portrange.GetToken()))
 299                                         e->records[item] = 1;
 300                         }
 301
 302                         e->banaction = str2banaction(tag->getString("action"));
 303                         e->duration = ServerInstance->Duration(tag->getString("duration", "60"));
 304
 305                         /* Use portparser for record replies */
 306
 307                         /* yeah, logic here is a little messy */
 308                         if ((e->bitmask <= 0) && (DNSBLConfEntry::A_BITMASK == e->type))
 309                         {
 310                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(%s): invalid bitmask",tag->getTagLocation().c_str());
 311                         }
 312                         else if (e->name.empty())
 313                         {
 314                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(%s): Invalid name",tag->getTagLocation().c_str());
 315                         }
 316                         else if (e->domain.empty())
 317                         {
 318                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(%s): Invalid domain",tag->getTagLocation().c_str());
 319                         }
 320                         else if (e->banaction == DNSBLConfEntry::I_UNKNOWN)
 321                         {
 322                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(%s): Invalid banaction",tag->getTagLocation().c_str());
 323                         }
 324                         else if (e->duration <= 0)
 325                         {
 326                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(%s): Invalid duration",tag->getTagLocation().c_str());
 327                         }
 328                         else
 329                         {
 330                                 if (e->reason.empty())
 331                                 {
 332                                         ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(%s): empty reason, using defaults",tag->getTagLocation().c_str());
 333                                         e->reason = "Your IP has been blacklisted.";
 334                                 }
 335
 336                                 /* add it, all is ok */
 337                                 DNSBLConfEntries.push_back(e);
 338                                 continue;
 339                         }
 340
 341                         /* delete and drop it, error somewhere */
 342                         delete e;
 343                 }
 344         }
 345
 346         void OnRehash(User* user)
 347         {
 348                 ReadConf();
 349         }
 350
 351         void OnUserInit(LocalUser* user)
 352         {
 353                 if (user->exempt)
 354                         return;
 355
 356                 unsigned char a, b, c, d;
 357                 char reversedipbuf[128];
 358                 std::string reversedip;
 359
 360                 if (user->client_sa.sa.sa_family != AF_INET)
 361                         return;
 362
 363                 d = (unsigned char) (user->client_sa.in4.sin_addr.s_addr >> 24) & 0xFF;
 364                 c = (unsigned char) (user->client_sa.in4.sin_addr.s_addr >> 16) & 0xFF;
 365                 b = (unsigned char) (user->client_sa.in4.sin_addr.s_addr >> 8) & 0xFF;
 366                 a = (unsigned char) user->client_sa.in4.sin_addr.s_addr & 0xFF;
 367
 368                 snprintf(reversedipbuf, 128, "%d.%d.%d.%d", d, c, b, a);
 369                 reversedip = std::string(reversedipbuf);
 370
 371                 // For each DNSBL, we will run through this lookup
 372                 unsigned int i = 0;
 373                 while (i < DNSBLConfEntries.size())
 374                 {
 375                         // Fill hostname with a dnsbl style host (d.c.b.a.domain.tld)
 376                         std::string hostname = reversedip + "." + DNSBLConfEntries[i]->domain;
 377
 378                         /* now we'd need to fire off lookups for `hostname'. */
 379                         bool cached;
 380                         DNSBLResolver *r = new DNSBLResolver(this, nameExt, countExt, hostname, user, DNSBLConfEntries[i], cached);
 381                         ServerInstance->AddResolver(r, cached);
 382                         i++;
 383                 }
 384                 countExt.set(user, i);
 385         }
 386
 387         ModResult OnSetConnectClass(LocalUser* user, ConnectClass* myclass)
 388         {
 389                 std::string dnsbl;
 390                 if (!myclass->config->readString("dnsbl", dnsbl))
 391                         return MOD_RES_PASSTHRU;
 392                 std::string* match = nameExt.get(user);
 393                 std::string myname = match ? *match : "";
 394                 if (dnsbl == myname)
 395                         return MOD_RES_PASSTHRU;
 396                 return MOD_RES_DENY;
 397         }
 398
 399         ModResult OnCheckReady(LocalUser *user)
 400         {
 401                 if (countExt.get(user))
 402                         return MOD_RES_DENY;
 403                 return MOD_RES_PASSTHRU;
 404         }
 405
 406         ModResult OnStats(char symbol, User* user, string_list &results)
 407         {
 408                 if (symbol != 'd')
 409                         return MOD_RES_PASSTHRU;
 410
 411                 unsigned long total_hits = 0, total_misses = 0;
 412
 413                 for (std::vector<DNSBLConfEntry*>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 414                 {
 415                         total_hits += (*i)->stats_hits;
 416                         total_misses += (*i)->stats_misses;
 417
 418                         results.push_back(std::string(ServerInstance->Config->ServerName.c_str()) + " 304 " + user->nick + " :DNSBLSTATS DNSbl \"" + (*i)->name + "\" had " +
 419                                         ConvToStr((*i)->stats_hits) + " hits and " + ConvToStr((*i)->stats_misses) + " misses");
 420                 }
 421
 422                 results.push_back(std::string(ServerInstance->Config->ServerName.c_str()) + " 304 " + user->nick + " :DNSBLSTATS Total hits: " + ConvToStr(total_hits));
 423                 results.push_back(std::string(ServerInstance->Config->ServerName.c_str()) + " 304 " + user->nick + " :DNSBLSTATS Total misses: " + ConvToStr(total_misses));
 424
 425                 return MOD_RES_PASSTHRU;
 426         }
 427 };
 428
 429 MODULE_INIT(ModuleDNSBL)