src/modules/m_dnsbl.cpp

   1 /*       +------------------------------------+
   2  *       | Inspire Internet Relay Chat Daemon |
   3  *       +------------------------------------+
   4  *
   5  *  InspIRCd: (C) 2002-2008 InspIRCd Development Team
   6  * See: http://www.inspircd.org/wiki/index.php/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
  28 {
  29         public:
  30                 enum EnumBanaction { I_UNKNOWN, I_KILL, I_ZLINE, I_KLINE, I_GLINE };
  31                 enum EnumType { A_RECORD, A_BITMASK };
  32                 std::string name, 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 *ServerInstance, const std::string &hostname, User* u, int userfd, DNSBLConfEntry *conf, bool &cached)
  55                 : Resolver(ServerInstance, 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, int resultnum = 0)
  64         {
  65                 /* for bitmask reply types, we arent interested in any but the first result (number 0) */
  66                 if ((ConfEntry->type == DNSBLConfEntry::A_BITMASK) && (resultnum))
  67                         return;
  68
  69                 /* Check the user still exists */
  70                 if ((them) && (them == ServerInstance->SE->GetRef(theirfd)))
  71                 {
  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 show = false, 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                                                         User::QuitUser(ServerInstance, them, std::string("Killed (") + reason + ")");
 112                                                         break;
 113                                                 }
 114                                                 case DNSBLConfEntry::I_KLINE:
 115                                                 {
 116                                                         KLine* kl = new KLine(ServerInstance, ServerInstance->Time(), ConfEntry->duration, ServerInstance->Config->ServerName, reason.c_str(),
 117                                                                         "*", them->GetIPString());
 118                                                         if (ServerInstance->XLines->AddLine(kl,NULL))
 119                                                         {
 120                                                                 ServerInstance->XLines->ApplyLines();
 121                                                         }
 122                                                         else
 123                                                                 delete kl;
 124                                                         break;
 125                                                 }
 126                                                 case DNSBLConfEntry::I_GLINE:
 127                                                 {
 128                                                         GLine* gl = new GLine(ServerInstance, ServerInstance->Time(), ConfEntry->duration, ServerInstance->Config->ServerName, reason.c_str(),
 129                                                                         "*", them->GetIPString());
 130                                                         if (ServerInstance->XLines->AddLine(gl,NULL))
 131                                                         {
 132                                                                 ServerInstance->XLines->ApplyLines();
 133                                                         }
 134                                                         else
 135                                                                 delete gl;
 136                                                         break;
 137                                                 }
 138                                                 case DNSBLConfEntry::I_ZLINE:
 139                                                 {
 140                                                         ZLine* zl = new ZLine(ServerInstance, ServerInstance->Time(), ConfEntry->duration, ServerInstance->Config->ServerName, reason.c_str(),
 141                                                                         them->GetIPString());
 142                                                         if (ServerInstance->XLines->AddLine(zl,NULL))
 143                                                         {
 144                                                                 ServerInstance->XLines->ApplyLines();
 145                                                         }
 146                                                         else
 147                                                                 delete zl;
 148                                                         break;
 149                                                 }
 150                                                 case DNSBLConfEntry::I_UNKNOWN:
 151                                                 {
 152                                                         break;
 153                                                 }
 154                                                 break;
 155                                         }
 156
 157                                         if (show)
 158                                         {
 159                                                 ServerInstance->SNO->WriteToSnoMask('O', "Connecting user %s detected as being on a DNS blacklist (%s) with result %d", them->GetFullRealHost(), ConfEntry->name.c_str(), bitmask);
 160                                         }
 161                                 }
 162                                 else
 163                                         ConfEntry->stats_misses++;
 164                         }
 165                         else
 166                                 ConfEntry->stats_misses++;
 167                 }
 168         }
 169
 170         virtual void OnError(ResolverError e, const std::string &errormessage)
 171         {
 172         }
 173
 174         virtual ~DNSBLResolver()
 175         {
 176         }
 177 };
 178
 179 class ModuleDNSBL : public Module
 180 {
 181  private:
 182         std::vector<DNSBLConfEntry *> DNSBLConfEntries;
 183
 184         /*
 185          *      Convert a string to EnumBanaction
 186          */
 187         DNSBLConfEntry::EnumBanaction str2banaction(const std::string &action)
 188         {
 189                 if(action.compare("KILL")==0)
 190                         return DNSBLConfEntry::I_KILL;
 191                 if(action.compare("KLINE")==0)
 192                         return DNSBLConfEntry::I_KLINE;
 193                 if(action.compare("ZLINE")==0)
 194                         return DNSBLConfEntry::I_ZLINE;
 195                 if(action.compare("GLINE")==0)
 196                         return DNSBLConfEntry::I_GLINE;
 197
 198                 return DNSBLConfEntry::I_UNKNOWN;
 199         }
 200  public:
 201         ModuleDNSBL(InspIRCd *Me) : Module(Me)
 202         {
 203                 ReadConf();
 204                 Implementation eventlist[] = { I_OnRehash, I_OnUserRegister, I_OnStats };
 205                 ServerInstance->Modules->Attach(eventlist, this, 3);
 206         }
 207
 208         virtual ~ModuleDNSBL()
 209         {
 210                 ClearEntries();
 211         }
 212
 213         virtual Version GetVersion()
 214         {
 215                 return Version(2, 0, 0, 1, VF_VENDOR, API_VERSION);
 216         }
 217
 218
 219         /** Clear entries and free the mem it was using
 220          */
 221         void ClearEntries()
 222         {
 223                 std::vector<DNSBLConfEntry *>::iterator i;
 224                 for (std::vector<DNSBLConfEntry *>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 225                         delete *i;
 226                 DNSBLConfEntries.clear();
 227         }
 228
 229         /** Fill our conf vector with data
 230          */
 231         virtual void ReadConf()
 232         {
 233                 ConfigReader *MyConf = new ConfigReader(ServerInstance);
 234                 ClearEntries();
 235
 236                 for (int i=0; i< MyConf->Enumerate("dnsbl"); i++)
 237                 {
 238                         DNSBLConfEntry *e = new DNSBLConfEntry();
 239
 240                         e->name = MyConf->ReadValue("dnsbl", "name", i);
 241                         e->reason = MyConf->ReadValue("dnsbl", "reason", i);
 242                         e->domain = MyConf->ReadValue("dnsbl", "domain", i);
 243
 244                         if (MyConf->ReadValue("dnsbl", "type", i) == "bitmask")
 245                         {
 246                                 e->type = DNSBLConfEntry::A_BITMASK;
 247                                 e->bitmask = MyConf->ReadInteger("dnsbl", "bitmask", i, false);
 248                         }
 249                         else
 250                         {
 251                                 memset(e->records, 0, 256);
 252                                 e->type = DNSBLConfEntry::A_RECORD;
 253                                 irc::portparser portrange(MyConf->ReadValue("dnsbl", "records", i), false);
 254                                 long item = -1;
 255                                 while ((item = portrange.GetToken()))
 256                                         e->records[item] = 1;
 257                         }
 258
 259                         e->banaction = str2banaction(MyConf->ReadValue("dnsbl", "action", i));
 260                         e->duration = ServerInstance->Duration(MyConf->ReadValue("dnsbl", "duration", i));
 261
 262                         /* Use portparser for record replies */
 263
 264                         /* yeah, logic here is a little messy */
 265                         if (e->bitmask <= 0)
 266                         {
 267                                 ServerInstance->SNO->WriteToSnoMask('O', "DNSBL(#%d): invalid bitmask",i);
 268                         }
 269                         else if (e->name.empty())
 270                         {
 271                                 ServerInstance->SNO->WriteToSnoMask('O', "DNSBL(#%d): Invalid name",i);
 272                         }
 273                         else if (e->domain.empty())
 274                         {
 275                                 ServerInstance->SNO->WriteToSnoMask('O', "DNSBL(#%d): Invalid domain",i);
 276                         }
 277                         else if (e->banaction == DNSBLConfEntry::I_UNKNOWN)
 278                         {
 279                                 ServerInstance->SNO->WriteToSnoMask('O', "DNSBL(#%d): Invalid banaction", i);
 280                         }
 281                         else
 282                         {
 283                                 if (e->reason.empty())
 284                                 {
 285                                         ServerInstance->SNO->WriteToSnoMask('O', "DNSBL(#%d): empty reason, using defaults",i);
 286                                         e->reason = "Your IP has been blacklisted.";
 287                                 }
 288
 289                                 /* add it, all is ok */
 290                                 DNSBLConfEntries.push_back(e);
 291                                 continue;
 292                         }
 293
 294                         /* delete and drop it, error somewhere */
 295                         delete e;
 296                 }
 297
 298                 delete MyConf;
 299         }
 300
 301         virtual void OnRehash(User* user, const std::string &parameter)
 302         {
 303                 ReadConf();
 304         }
 305
 306         virtual int OnUserRegister(User* user)
 307         {
 308                 /* only do lookups on local users */
 309                 if (IS_LOCAL(user))
 310                 {
 311                         /* following code taken from bopm, reverses an IP address. */
 312                         struct in_addr in;
 313                         unsigned char a, b, c, d;
 314                         char reversedipbuf[128];
 315                         std::string reversedip;
 316                         bool success = false;
 317
 318                         if (!inet_aton(user->GetIPString(), &in))
 319                         {
 320 #ifdef IPV6
 321                                 /* We could have an ipv6 address here */
 322                                 std::string x = user->GetIPString();
 323                                 /* Is it a 4in6 address? (Compensate for this kernel kludge that people love) */
 324                                 if (x.find("0::ffff:") == 0)
 325                                 {
 326                                         x.erase(x.begin(), x.begin() + 8);
 327                                         if (inet_aton(x.c_str(), &in))
 328                                                 success = true;
 329                                 }
 330 #endif
 331                         }
 332                         else
 333                         {
 334                                 success = true;
 335                         }
 336
 337                         if (!success)
 338                                 return 0;
 339
 340                         d = (unsigned char) (in.s_addr >> 24) & 0xFF;
 341                         c = (unsigned char) (in.s_addr >> 16) & 0xFF;
 342                         b = (unsigned char) (in.s_addr >> 8) & 0xFF;
 343                         a = (unsigned char) in.s_addr & 0xFF;
 344
 345                         snprintf(reversedipbuf, 128, "%d.%d.%d.%d", d, c, b, a);
 346                         reversedip = std::string(reversedipbuf);
 347
 348                         // For each DNSBL, we will run through this lookup
 349                         for (std::vector<DNSBLConfEntry *>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 350                         {
 351                                 // Fill hostname with a dnsbl style host (d.c.b.a.domain.tld)
 352                                 std::string hostname = reversedip + "." + (*i)->domain;
 353
 354                                 /* now we'd need to fire off lookups for `hostname'. */
 355                                 bool cached;
 356                                 DNSBLResolver *r = new DNSBLResolver(this, ServerInstance, hostname, user, user->GetFd(), *i, cached);
 357                                 ServerInstance->AddResolver(r, cached);
 358                         }
 359                 }
 360
 361                 /* don't do anything with this hot potato */
 362                 return 0;
 363         }
 364
 365         virtual int OnStats(char symbol, User* user, string_list &results)
 366         {
 367                 if (symbol != 'd')
 368                         return 0;
 369
 370                 unsigned long total_hits = 0, total_misses = 0;
 371
 372                 for (std::vector<DNSBLConfEntry*>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 373                 {
 374                         total_hits += (*i)->stats_hits;
 375                         total_misses += (*i)->stats_misses;
 376
 377                         results.push_back(std::string(ServerInstance->Config->ServerName) + " 304 " + user->nick + " :DNSBLSTATS DNSbl \"" + (*i)->name + "\" had " +
 378                                         ConvToStr((*i)->stats_hits) + " hits and " + ConvToStr((*i)->stats_misses) + " misses");
 379                 }
 380
 381                 results.push_back(std::string(ServerInstance->Config->ServerName) + " 304 " + user->nick + " :DNSBLSTATS Total hits: " + ConvToStr(total_hits));
 382                 results.push_back(std::string(ServerInstance->Config->ServerName) + " 304 " + user->nick + " :DNSBLSTATS Total misses: " + ConvToStr(total_misses));
 383
 384                 return 0;
 385         }
 386 };
 387
 388 MODULE_INIT(ModuleDNSBL)