src/modules/m_dnsbl.cpp

   1 /*       +------------------------------------+
   2  *       | Inspire Internet Relay Chat Daemon |
   3  *       +------------------------------------+
   4  *
   5  *  InspIRCd: (C) 2002-2009 InspIRCd Development Team
   6  * See: http://wiki.inspircd.org/Credits
   7  *
   8  * This program is free but copyrighted software; see
   9  *            the file COPYING for details.
  10  *
  11  * ---------------------------------------------------
  12  */
  13
  14 #include "inspircd.h"
  15 #include "xline.h"
  16
  17 #ifndef WINDOWS
  18 #include <sys/types.h>
  19 #include <sys/socket.h>
  20 #include <netinet/in.h>
  21 #include <arpa/inet.h>
  22 #endif
  23
  24 /* $ModDesc: Provides handling of DNS blacklists */
  25
  26 /* Class holding data for a single entry */
  27 class DNSBLConfEntry : public classbase
  28 {
  29         public:
  30                 enum EnumBanaction { I_UNKNOWN, I_KILL, I_ZLINE, I_KLINE, I_GLINE, I_MARK };
  31                 enum EnumType { A_RECORD, A_BITMASK };
  32                 std::string name, ident, host, domain, reason;
  33                 EnumBanaction banaction;
  34                 EnumType type;
  35                 long duration;
  36                 int bitmask;
  37                 unsigned char records[256];
  38                 unsigned long stats_hits, stats_misses;
  39                 DNSBLConfEntry(): type(A_BITMASK),duration(86400),bitmask(0),stats_hits(0), stats_misses(0) {}
  40                 ~DNSBLConfEntry() { }
  41 };
  42
  43
  44 /** Resolver for CGI:IRC hostnames encoded in ident/GECOS
  45  */
  46 class DNSBLResolver : public Resolver
  47 {
  48         int theirfd;
  49         User* them;
  50         DNSBLConfEntry *ConfEntry;
  51
  52  public:
  53
  54         DNSBLResolver(Module *me, InspIRCd *Instance, const std::string &hostname, User* u, int userfd, DNSBLConfEntry *conf, bool &cached)
  55                 : Resolver(Instance, hostname, DNS_QUERY_A, cached, me)
  56         {
  57                 theirfd = userfd;
  58                 them = u;
  59                 ConfEntry = conf;
  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                 if ((them) && (them == ServerInstance->SE->GetRef(theirfd)))
  67                 {
  68                         // Now we calculate the bitmask: 256*(256*(256*a+b)+c)+d
  69                         if(result.length())
  70                         {
  71                                 unsigned int bitmask = 0, record = 0;
  72                                 bool match = false;
  73                                 in_addr resultip;
  74
  75                                 inet_aton(result.c_str(), &resultip);
  76
  77                                 switch (ConfEntry->type)
  78                                 {
  79                                         case DNSBLConfEntry::A_BITMASK:
  80                                                 bitmask = resultip.s_addr >> 24; /* Last octet (network byte order) */
  81                                                 bitmask &= ConfEntry->bitmask;
  82                                                 match = (bitmask != 0);
  83                                         break;
  84                                         case DNSBLConfEntry::A_RECORD:
  85                                                 record = resultip.s_addr >> 24; /* Last octet */
  86                                                 match = (ConfEntry->records[record] == 1);
  87                                         break;
  88                                 }
  89
  90                                 if (match)
  91                                 {
  92                                         std::string reason = ConfEntry->reason;
  93                                         std::string::size_type x = reason.find("%ip%");
  94                                         while (x != std::string::npos)
  95                                         {
  96                                                 reason.erase(x, 4);
  97                                                 reason.insert(x, them->GetIPString());
  98                                                 x = reason.find("%ip%");
  99                                         }
 100
 101                                         ConfEntry->stats_hits++;
 102
 103                                         switch (ConfEntry->banaction)
 104                                         {
 105                                                 case DNSBLConfEntry::I_KILL:
 106                                                 {
 107                                                         ServerInstance->Users->QuitUser(them, std::string("Killed (") + reason + ")");
 108                                                         break;
 109                                                 }
 110                                                 case DNSBLConfEntry::I_MARK:
 111                                                 {
 112                                                         if (!ConfEntry->ident.empty())
 113                                                         {
 114                                                                 them->WriteServ("304 " + them->nick + " :Your ident has been set to " + ConfEntry->ident + " because you matched " + reason);
 115                                                                 them->ChangeIdent(ConfEntry->ident.c_str());
 116                                                         }
 117
 118                                                         if (!ConfEntry->host.empty())
 119                                                         {
 120                                                                 them->WriteServ("304 " + them->nick + " :Your host has been set to " + ConfEntry->host + " because you matched " + reason);
 121                                                                 them->ChangeDisplayedHost(ConfEntry->host.c_str());
 122                                                         }
 123
 124                                                         break;
 125                                                 }
 126                                                 case DNSBLConfEntry::I_KLINE:
 127                                                 {
 128                                                         KLine* kl = new KLine(ServerInstance, ServerInstance->Time(), ConfEntry->duration, ServerInstance->Config->ServerName, reason.c_str(),
 129                                                                         "*", them->GetIPString());
 130                                                         if (ServerInstance->XLines->AddLine(kl,NULL))
 131                                                         {
 132                                                                 ServerInstance->SNO->WriteGlobalSno('x',"K:line added due to DNSBL match on *@%s to expire on %s: %s",
 133                                                                         them->GetIPString(), ServerInstance->TimeString(kl->expiry).c_str(), reason.c_str());
 134                                                                 ServerInstance->XLines->ApplyLines();
 135                                                         }
 136                                                         else
 137                                                                 delete kl;
 138                                                         break;
 139                                                 }
 140                                                 case DNSBLConfEntry::I_GLINE:
 141                                                 {
 142                                                         GLine* gl = new GLine(ServerInstance, ServerInstance->Time(), ConfEntry->duration, ServerInstance->Config->ServerName, reason.c_str(),
 143                                                                         "*", them->GetIPString());
 144                                                         if (ServerInstance->XLines->AddLine(gl,NULL))
 145                                                         {
 146                                                                 ServerInstance->SNO->WriteGlobalSno('x',"G:line added due to DNSBL match on *@%s to expire on %s: %s",
 147                                                                         them->GetIPString(), ServerInstance->TimeString(gl->expiry).c_str(), reason.c_str());
 148                                                                 ServerInstance->XLines->ApplyLines();
 149                                                         }
 150                                                         else
 151                                                                 delete gl;
 152                                                         break;
 153                                                 }
 154                                                 case DNSBLConfEntry::I_ZLINE:
 155                                                 {
 156                                                         ZLine* zl = new ZLine(ServerInstance, ServerInstance->Time(), ConfEntry->duration, ServerInstance->Config->ServerName, reason.c_str(),
 157                                                                         them->GetIPString());
 158                                                         if (ServerInstance->XLines->AddLine(zl,NULL))
 159                                                         {
 160                                                                 ServerInstance->SNO->WriteGlobalSno('x',"Z:line added due to DNSBL match on *@%s to expire on %s: %s",
 161                                                                         them->GetIPString(), ServerInstance->TimeString(zl->expiry).c_str(), reason.c_str());
 162                                                                 ServerInstance->XLines->ApplyLines();
 163                                                         }
 164                                                         else
 165                                                                 delete zl;
 166                                                         break;
 167                                                 }
 168                                                 case DNSBLConfEntry::I_UNKNOWN:
 169                                                 {
 170                                                         break;
 171                                                 }
 172                                                 break;
 173                                         }
 174
 175                                         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);
 176                                 }
 177                                 else
 178                                         ConfEntry->stats_misses++;
 179                         }
 180                         else
 181                                 ConfEntry->stats_misses++;
 182                 }
 183         }
 184
 185         virtual void OnError(ResolverError e, const std::string &errormessage)
 186         {
 187         }
 188
 189         virtual ~DNSBLResolver()
 190         {
 191         }
 192 };
 193
 194 class ModuleDNSBL : public Module
 195 {
 196  private:
 197         std::vector<DNSBLConfEntry *> DNSBLConfEntries;
 198
 199         /*
 200          *      Convert a string to EnumBanaction
 201          */
 202         DNSBLConfEntry::EnumBanaction str2banaction(const std::string &action)
 203         {
 204                 if(action.compare("KILL")==0)
 205                         return DNSBLConfEntry::I_KILL;
 206                 if(action.compare("KLINE")==0)
 207                         return DNSBLConfEntry::I_KLINE;
 208                 if(action.compare("ZLINE")==0)
 209                         return DNSBLConfEntry::I_ZLINE;
 210                 if(action.compare("GLINE")==0)
 211                         return DNSBLConfEntry::I_GLINE;
 212                 if(action.compare("MARK")==0)
 213                         return DNSBLConfEntry::I_MARK;
 214
 215                 return DNSBLConfEntry::I_UNKNOWN;
 216         }
 217  public:
 218         ModuleDNSBL(InspIRCd *Me) : Module(Me)
 219         {
 220                 ReadConf();
 221                 Implementation eventlist[] = { I_OnRehash, I_OnUserRegister, I_OnStats };
 222                 ServerInstance->Modules->Attach(eventlist, this, 3);
 223         }
 224
 225         virtual ~ModuleDNSBL()
 226         {
 227                 ClearEntries();
 228         }
 229
 230         virtual Version GetVersion()
 231         {
 232                 return Version("Provides handling of DNS blacklists", VF_VENDOR, API_VERSION);
 233         }
 234
 235
 236         /** Clear entries and free the mem it was using
 237          */
 238         void ClearEntries()
 239         {
 240                 for (std::vector<DNSBLConfEntry *>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 241                         delete *i;
 242                 DNSBLConfEntries.clear();
 243         }
 244
 245         /** Fill our conf vector with data
 246          */
 247         virtual void ReadConf()
 248         {
 249                 ConfigReader *MyConf = new ConfigReader(ServerInstance);
 250                 ClearEntries();
 251
 252                 for (int i=0; i< MyConf->Enumerate("dnsbl"); i++)
 253                 {
 254                         DNSBLConfEntry *e = new DNSBLConfEntry();
 255
 256                         e->name = MyConf->ReadValue("dnsbl", "name", i);
 257                         e->ident = MyConf->ReadValue("dnsbl", "ident", i);
 258                         e->host = MyConf->ReadValue("dnsbl", "host", i);
 259                         e->reason = MyConf->ReadValue("dnsbl", "reason", i);
 260                         e->domain = MyConf->ReadValue("dnsbl", "domain", i);
 261
 262                         if (MyConf->ReadValue("dnsbl", "type", i) == "bitmask")
 263                         {
 264                                 e->type = DNSBLConfEntry::A_BITMASK;
 265                                 e->bitmask = MyConf->ReadInteger("dnsbl", "bitmask", i, false);
 266                         }
 267                         else
 268                         {
 269                                 memset(e->records, 0, sizeof(e->records));
 270                                 e->type = DNSBLConfEntry::A_RECORD;
 271                                 irc::portparser portrange(MyConf->ReadValue("dnsbl", "records", i), false);
 272                                 long item = -1;
 273                                 while ((item = portrange.GetToken()))
 274                                         e->records[item] = 1;
 275                         }
 276
 277                         e->banaction = str2banaction(MyConf->ReadValue("dnsbl", "action", i));
 278                         e->duration = ServerInstance->Duration(MyConf->ReadValue("dnsbl", "duration", "60", i));
 279
 280                         /* Use portparser for record replies */
 281
 282                         /* yeah, logic here is a little messy */
 283                         if ((e->bitmask <= 0) && (DNSBLConfEntry::A_BITMASK == e->type))
 284                         {
 285                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(#%d): invalid bitmask",i);
 286                         }
 287                         else if (e->name.empty())
 288                         {
 289                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(#%d): Invalid name",i);
 290                         }
 291                         else if (e->domain.empty())
 292                         {
 293                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(#%d): Invalid domain",i);
 294                         }
 295                         else if (e->banaction == DNSBLConfEntry::I_UNKNOWN)
 296                         {
 297                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(#%d): Invalid banaction", i);
 298                         }
 299                         else if (e->duration <= 0)
 300                         {
 301                                 ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(#%d): Invalid duration", i);
 302                         }
 303                         else
 304                         {
 305                                 if (e->reason.empty())
 306                                 {
 307                                         ServerInstance->SNO->WriteGlobalSno('a', "DNSBL(#%d): empty reason, using defaults",i);
 308                                         e->reason = "Your IP has been blacklisted.";
 309                                 }
 310
 311                                 /* add it, all is ok */
 312                                 DNSBLConfEntries.push_back(e);
 313                                 continue;
 314                         }
 315
 316                         /* delete and drop it, error somewhere */
 317                         delete e;
 318                 }
 319
 320                 delete MyConf;
 321         }
 322
 323         virtual void OnRehash(User* user)
 324         {
 325                 ReadConf();
 326         }
 327
 328         virtual ModResult OnUserRegister(User* user)
 329         {
 330                 /* only do lookups on local users */
 331                 if (IS_LOCAL(user))
 332                 {
 333                         /* following code taken from bopm, reverses an IP address. */
 334                         struct in_addr in;
 335                         unsigned char a, b, c, d;
 336                         char reversedipbuf[128];
 337                         std::string reversedip;
 338                         bool success;
 339
 340                         success = inet_aton(user->GetIPString(), &in);
 341
 342                         if (!success)
 343                                 return MOD_RES_PASSTHRU;
 344
 345                         d = (unsigned char) (in.s_addr >> 24) & 0xFF;
 346                         c = (unsigned char) (in.s_addr >> 16) & 0xFF;
 347                         b = (unsigned char) (in.s_addr >> 8) & 0xFF;
 348                         a = (unsigned char) in.s_addr & 0xFF;
 349
 350                         snprintf(reversedipbuf, 128, "%d.%d.%d.%d", d, c, b, a);
 351                         reversedip = std::string(reversedipbuf);
 352
 353                         // For each DNSBL, we will run through this lookup
 354                         for (std::vector<DNSBLConfEntry *>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 355                         {
 356                                 // Fill hostname with a dnsbl style host (d.c.b.a.domain.tld)
 357                                 std::string hostname = reversedip + "." + (*i)->domain;
 358
 359                                 /* now we'd need to fire off lookups for `hostname'. */
 360                                 bool cached;
 361                                 DNSBLResolver *r = new DNSBLResolver(this, ServerInstance, hostname, user, user->GetFd(), *i, cached);
 362                                 ServerInstance->AddResolver(r, cached);
 363                         }
 364                 }
 365
 366                 /* don't do anything with this hot potato */
 367                 return MOD_RES_PASSTHRU;
 368         }
 369
 370         virtual ModResult OnStats(char symbol, User* user, string_list &results)
 371         {
 372                 if (symbol != 'd')
 373                         return MOD_RES_PASSTHRU;
 374
 375                 unsigned long total_hits = 0, total_misses = 0;
 376
 377                 for (std::vector<DNSBLConfEntry*>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 378                 {
 379                         total_hits += (*i)->stats_hits;
 380                         total_misses += (*i)->stats_misses;
 381
 382                         results.push_back(std::string(ServerInstance->Config->ServerName) + " 304 " + user->nick + " :DNSBLSTATS DNSbl \"" + (*i)->name + "\" had " +
 383                                         ConvToStr((*i)->stats_hits) + " hits and " + ConvToStr((*i)->stats_misses) + " misses");
 384                 }
 385
 386                 results.push_back(std::string(ServerInstance->Config->ServerName) + " 304 " + user->nick + " :DNSBLSTATS Total hits: " + ConvToStr(total_hits));
 387                 results.push_back(std::string(ServerInstance->Config->ServerName) + " 304 " + user->nick + " :DNSBLSTATS Total misses: " + ConvToStr(total_misses));
 388
 389                 return MOD_RES_PASSTHRU;
 390         }
 391 };
 392
 393 MODULE_INIT(ModuleDNSBL)