src/modules/m_dnsbl.cpp

   1 /*       +------------------------------------+
   2  *       | Inspire Internet Relay Chat Daemon |
   3  *       +------------------------------------+
   4  *
   5  *  InspIRCd: (C) 2002-2007 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 <sys/types.h>
  15 #include <sys/socket.h>
  16 #include <netinet/in.h>
  17 #include <arpa/inet.h>
  18 #include <stdint.h>
  19 #include "inspircd.h"
  20 #include "dns.h"
  21 #include "users.h"
  22 #include "channels.h"
  23 #include "modules.h"
  24
  25 /* $ModDesc: Provides handling of DNS blacklists */
  26
  27 /* Class holding data for a single entry */
  28 class DNSBLConfEntry
  29 {
  30         public:
  31                 enum EnumBanaction { I_UNKNOWN, I_KILL, I_ZLINE, I_KLINE, I_GLINE };
  32                 std::string name, domain, reason;
  33                 EnumBanaction banaction;
  34                 long duration;
  35                 int bitmask;
  36                 DNSBLConfEntry(): duration(86400),bitmask(0) {}
  37 };
  38
  39
  40 /** Resolver for CGI:IRC hostnames encoded in ident/GECOS
  41  */
  42 class DNSBLResolver : public Resolver
  43 {
  44         int theirfd;
  45         userrec* them;
  46         DNSBLConfEntry *ConfEntry;
  47
  48     public:
  49         DNSBLResolver(Module *me, InspIRCd *ServerInstance, const std::string &hostname, userrec* u, int userfd, DNSBLConfEntry *conf, bool &cached)
  50                 : Resolver(ServerInstance, hostname, DNS_QUERY_A, cached, me)
  51         {
  52                 theirfd = userfd;
  53                 them = u;
  54                 ConfEntry = conf;
  55         }
  56
  57         virtual void OnLookupComplete(const std::string &result, unsigned int ttl, bool cached)
  58         {
  59                 /* Check the user still exists */
  60                 if ((them) && (them == ServerInstance->SE->GetRef(theirfd)))
  61                 {
  62                         // Now we calculate the bitmask: 256*(256*(256*a+b)+c)+d
  63                         if(result.length())
  64                         {
  65                                 unsigned int bitmask=0;
  66                                 unsigned int octetpos=0;
  67                                 std::string tmp = result;
  68
  69                                 while(tmp.length()>0)
  70                                 {
  71                                         std::string octet;
  72                                         /* Fix by brain, npos is -1, so unsigned int will never match */
  73                                         std::string::size_type lastdot = tmp.rfind(".");
  74
  75                                         if (lastdot == std::string::npos)
  76                                         {
  77                                                 octet=tmp;
  78                                                 tmp.clear();
  79                                         }
  80                                         else
  81                                         {
  82                                                 octet=tmp.substr(lastdot+1,tmp.length()-lastdot+1);
  83                                                 tmp.resize(lastdot);
  84                                         }
  85
  86                                         bitmask += (256 ^ octetpos) * atoi(octet.c_str());
  87                                         octetpos += 1;
  88                                 }
  89
  90                                 bitmask &= ConfEntry->bitmask;
  91
  92                                 if (bitmask != 0)
  93                                 {
  94                                         std::string reason = ConfEntry->reason;
  95                                         std::string::size_type x = reason.find("%ip%");
  96                                         while (x != std::string::npos)
  97                                         {
  98                                                 reason.erase(x, 4);
  99                                                 reason.insert(x, them->GetIPString());
 100                                                 x = reason.find("%ip%");
 101                                         }
 102
 103                                         ServerInstance->WriteOpers("*** Connecting user %s detected as being on a DNS blacklist (%s) with result %d", them->GetFullRealHost(), ConfEntry->name.c_str(), bitmask);
 104
 105                                         switch (ConfEntry->banaction)
 106                                         {
 107                                                 case DNSBLConfEntry::I_KILL:
 108                                                 {
 109                                                         userrec::QuitUser(ServerInstance, them, std::string("Killed (") + reason + ")");
 110                                                         break;
 111                                                 }
 112                                                 case DNSBLConfEntry::I_KLINE:
 113                                                 {
 114                                                         ServerInstance->AddKLine(ConfEntry->duration, ServerInstance->Config->ServerName, reason, std::string("*@") + them->GetIPString());
 115                                                         FOREACH_MOD(I_OnAddKLine,OnAddKLine(ServerInstance->Duration(ConfEntry->duration), NULL, reason, std::string("*@") + them->GetIPString()));
 116                                                         break;
 117                                                 }
 118                                                 case DNSBLConfEntry::I_GLINE:
 119                                                 {
 120                                                         ServerInstance->AddGLine(ConfEntry->duration, ServerInstance->Config->ServerName, reason, std::string("*@") + them->GetIPString());
 121                                                         FOREACH_MOD(I_OnAddGLine,OnAddGLine(ServerInstance->Duration(ConfEntry->duration), NULL, reason, std::string("*@") + them->GetIPString()));
 122                                                         break;
 123                                                 }
 124                                                 case DNSBLConfEntry::I_ZLINE:
 125                                                 {
 126                                                         ServerInstance->AddZLine(ConfEntry->duration, ServerInstance->Config->ServerName, reason, them->GetIPString());
 127                                             FOREACH_MOD(I_OnAddZLine,OnAddZLine(ServerInstance->Duration(ConfEntry->duration), NULL, reason, them->GetIPString()));
 128                                                         break;
 129                                                 }
 130                                                 case DNSBLConfEntry::I_UNKNOWN:
 131                                                 {
 132                                                         break;
 133                                                 }
 134                                                 break;
 135                                         }
 136                                 }
 137                         }
 138                 }
 139         }
 140
 141         virtual void OnError(ResolverError e, const std::string &errormessage)
 142         {
 143         }
 144
 145         virtual ~DNSBLResolver()
 146         {
 147         }
 148 };
 149
 150 class ModuleDNSBL : public Module
 151 {
 152  private:
 153         std::vector<DNSBLConfEntry *> DNSBLConfEntries;
 154
 155         /*
 156          *      Convert a string to EnumBanaction
 157          */
 158         DNSBLConfEntry::EnumBanaction str2banaction(const std::string &action)
 159         {
 160                 if(action.compare("KILL")==0)
 161                         return DNSBLConfEntry::I_KILL;
 162                 if(action.compare("KLINE")==0)
 163                         return DNSBLConfEntry::I_KLINE;
 164                 if(action.compare("ZLINE")==0)
 165                         return DNSBLConfEntry::I_ZLINE;
 166                 if(action.compare("GLINE")==0)
 167                         return DNSBLConfEntry::I_GLINE;
 168
 169                 return DNSBLConfEntry::I_UNKNOWN;
 170         }
 171  public:
 172         ModuleDNSBL(InspIRCd *Me) : Module::Module(Me)
 173         {
 174                 ReadConf();
 175         }
 176
 177         virtual ~ModuleDNSBL()
 178         {
 179                 ClearEntries();
 180         }
 181
 182         virtual Version GetVersion()
 183         {
 184                 return Version(2, 0, 0, 1, VF_VENDOR, API_VERSION);
 185         }
 186
 187         void Implements(char* List)
 188         {
 189                 List[I_OnRehash] = List[I_OnUserRegister] = 1;
 190         }
 191
 192         /** Clear entries and free the mem it was using
 193          */
 194         void ClearEntries()
 195         {
 196                 std::vector<DNSBLConfEntry *>::iterator i;
 197                 while ((i = DNSBLConfEntries.begin()) != DNSBLConfEntries.end())
 198                 {
 199                         DNSBLConfEntries.erase(i);
 200                         delete *i;
 201                 }
 202         }
 203
 204         /** Fill our conf vector with data
 205          */
 206         virtual void ReadConf()
 207         {
 208                 ConfigReader *MyConf = new ConfigReader(ServerInstance);
 209                 ClearEntries();
 210
 211                 for (int i=0; i< MyConf->Enumerate("dnsbl"); i++)
 212                 {
 213                         DNSBLConfEntry *e = new DNSBLConfEntry();
 214
 215                         e->name = MyConf->ReadValue("dnsbl", "name", i);
 216                         e->reason = MyConf->ReadValue("dnsbl", "reason", i);
 217                         e->domain = MyConf->ReadValue("dnsbl", "domain", i);
 218                         e->banaction = str2banaction(MyConf->ReadValue("dnsbl", "action", i));
 219                         e->duration = ServerInstance->Duration(MyConf->ReadValue("dnsbl", "duration", i).c_str());
 220                         e->bitmask = MyConf->ReadInteger("dnsbl", "bitmask", i, false);
 221
 222                         /* yeah, logic here is a little messy */
 223                         if (e->bitmask <= 0)
 224                         {
 225                                 ServerInstance->WriteOpers("*** DNSBL(#%d): invalid bitmask",i);
 226                         }
 227                         else if (e->name == "")
 228                         {
 229                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid name",i);
 230                         }
 231                         else if (e->domain == "")
 232                         {
 233                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid domain",i);
 234                         }
 235                         else if (e->banaction == DNSBLConfEntry::I_UNKNOWN)
 236                         {
 237                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid banaction", i);
 238                         }
 239                         else
 240                         {
 241                                 if (e->reason == "")
 242                                 {
 243                                         ServerInstance->WriteOpers("*** DNSBL(#%d): empty reason, using defaults",i);
 244                                         e->reason = "Your IP has been blacklisted.";
 245                                 }
 246
 247                                 /* add it, all is ok */
 248                                 DNSBLConfEntries.push_back(e);
 249                                 continue;
 250                         }
 251
 252                         /* delete and drop it, error somewhere */
 253                         delete e;
 254                 }
 255
 256                 delete MyConf;
 257         }
 258
 259         virtual void OnRehash(userrec* user, const std::string &parameter)
 260         {
 261                 ReadConf();
 262         }
 263
 264         /*
 265          * We will check each user that connects *locally* (userrec::fd>0)
 266          */
 267         virtual int OnUserRegister(userrec* user)
 268         {
 269                 if (IS_LOCAL(user))
 270                 {
 271                         /* following code taken from bopm, reverses an IP address. */
 272                         struct in_addr in;
 273                         unsigned char a, b, c, d;
 274                         char reversedipbuf[128];
 275                         std::string reversedip;
 276                         bool success = false;
 277
 278                         if (!inet_aton(user->GetIPString(), &in))
 279                         {
 280 #ifdef IPV6
 281                                 /* We could have an ipv6 address here */
 282                                 std::string x = user->GetIPString();
 283                                 /* Is it a 4in6 address? (Compensate for this kernel kludge that people love) */
 284                                 if (x.find("0::ffff:") == 0)
 285                                 {
 286                                         x.erase(x.begin(), x.begin() + 8);
 287                                         if (inet_aton(x.c_str(), &in))
 288                                                 success = true;
 289                                 }
 290 #endif
 291                         }
 292                         else
 293                         {
 294                                 success = true;
 295                         }
 296
 297                         if (!success)
 298                                 return 0;
 299
 300                         d = (unsigned char) (in.s_addr >> 24) & 0xFF;
 301                         c = (unsigned char) (in.s_addr >> 16) & 0xFF;
 302                         b = (unsigned char) (in.s_addr >> 8) & 0xFF;
 303                         a = (unsigned char) in.s_addr & 0xFF;
 304
 305                         snprintf(reversedipbuf, 128, "%d.%d.%d.%d", d, c, b, a);
 306                         reversedip = std::string(reversedipbuf);
 307
 308                         // For each DNSBL, we will run through this lookup
 309                         for (std::vector<DNSBLConfEntry *>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 310                         {
 311                                 // Fill hostname with a dnsbl style host (d.c.b.a.domain.tld)
 312                                 std::string hostname = reversedip + "." + (*i)->domain;
 313
 314                                 /* now we'd need to fire off lookups for `hostname'. */
 315                                 bool cached;
 316                                 DNSBLResolver *r = new DNSBLResolver(this, ServerInstance, hostname, user, user->GetFd(), *i, cached);
 317                                 ServerInstance->AddResolver(r, cached);
 318                         }
 319                 }
 320
 321                 /* don't do anything with this hot potato */
 322                 return 0;
 323         }
 324 };
 325
 326 // stuff down here is the module-factory stuff.
 327
 328 class ModuleDNSBLFactory : public ModuleFactory
 329 {
 330  public:
 331         ModuleDNSBLFactory()
 332         {
 333         }
 334
 335         ~ModuleDNSBLFactory()
 336         {
 337         }
 338
 339         virtual Module *CreateModule(InspIRCd *Me)
 340         {
 341                 return new ModuleDNSBL(Me);
 342         }
 343
 344 };
 345
 346
 347 extern "C" void * init_module( void )
 348 {
 349         return new ModuleDNSBLFactory;
 350 }