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                                                         break;
 116                                                 }
 117                                                 case DNSBLConfEntry::I_GLINE:
 118                                                 {
 119                                                         ServerInstance->AddGLine(ConfEntry->duration, ServerInstance->Config->ServerName, reason, std::string("*@") + them->GetIPString());
 120                                                         break;
 121                                                 }
 122                                                 case DNSBLConfEntry::I_ZLINE:
 123                                                 {
 124                                                         ServerInstance->AddZLine(ConfEntry->duration, ServerInstance->Config->ServerName, reason, them->GetIPString());
 125                                                         break;
 126                                                 }
 127                                                 case DNSBLConfEntry::I_UNKNOWN:
 128                                                 {
 129                                                         break;
 130                                                 }
 131                                                 break;
 132                                         }
 133                                 }
 134                         }
 135                 }
 136         }
 137
 138         virtual void OnError(ResolverError e, const std::string &errormessage)
 139         {
 140         }
 141
 142         virtual ~DNSBLResolver()
 143         {
 144         }
 145 };
 146
 147 class ModuleDNSBL : public Module
 148 {
 149  private:
 150         std::vector<DNSBLConfEntry *> DNSBLConfEntries;
 151
 152         /*
 153          *      Convert a string to EnumBanaction
 154          */
 155         DNSBLConfEntry::EnumBanaction str2banaction(const std::string &action)
 156         {
 157                 if(action.compare("KILL")==0)
 158                         return DNSBLConfEntry::I_KILL;
 159                 if(action.compare("KLINE")==0)
 160                         return DNSBLConfEntry::I_KLINE;
 161                 if(action.compare("ZLINE")==0)
 162                         return DNSBLConfEntry::I_ZLINE;
 163                 if(action.compare("GLINE")==0)
 164                         return DNSBLConfEntry::I_GLINE;
 165
 166                 return DNSBLConfEntry::I_UNKNOWN;
 167         }
 168  public:
 169         ModuleDNSBL(InspIRCd *Me) : Module::Module(Me)
 170         {
 171                 ReadConf();
 172         }
 173
 174         virtual ~ModuleDNSBL()
 175         {
 176                 ClearEntries();
 177         }
 178
 179         virtual Version GetVersion()
 180         {
 181                 return Version(2, 0, 0, 1, VF_VENDOR, API_VERSION);
 182         }
 183
 184         void Implements(char* List)
 185         {
 186                 List[I_OnRehash] = List[I_OnUserRegister] = 1;
 187         }
 188
 189         /** Clear entries and free the mem it was using
 190          */
 191         void ClearEntries()
 192         {
 193                 std::vector<DNSBLConfEntry *>::iterator i;
 194                 while ((i = DNSBLConfEntries.begin()) != DNSBLConfEntries.end())
 195                 {
 196                         DNSBLConfEntries.erase(i);
 197                         delete *i;
 198                 }
 199         }
 200
 201         /** Fill our conf vector with data
 202          */
 203         virtual void ReadConf()
 204         {
 205                 ConfigReader *MyConf = new ConfigReader(ServerInstance);
 206                 ClearEntries();
 207
 208                 for (int i=0; i< MyConf->Enumerate("dnsbl"); i++)
 209                 {
 210                         DNSBLConfEntry *e = new DNSBLConfEntry();
 211
 212                         e->name = MyConf->ReadValue("dnsbl", "name", i);
 213                         e->reason = MyConf->ReadValue("dnsbl", "reason", i);
 214                         e->domain = MyConf->ReadValue("dnsbl", "domain", i);
 215                         e->banaction = str2banaction(MyConf->ReadValue("dnsbl", "action", i));
 216                         e->duration = ServerInstance->Duration(MyConf->ReadValue("dnsbl", "duration", i).c_str());
 217                         e->bitmask = MyConf->ReadInteger("dnsbl", "bitmask", i, false);
 218
 219                         /* yeah, logic here is a little messy */
 220                         if (e->bitmask <= 0)
 221                         {
 222                                 ServerInstance->WriteOpers("*** DNSBL(#%d): invalid bitmask",i);
 223                         }
 224                         else if (e->name == "")
 225                         {
 226                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid name",i);
 227                         }
 228                         else if (e->domain == "")
 229                         {
 230                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid domain",i);
 231                         }
 232                         else if (e->banaction == DNSBLConfEntry::I_UNKNOWN)
 233                         {
 234                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid banaction", i);
 235                         }
 236                         else
 237                         {
 238                                 if (e->reason == "")
 239                                 {
 240                                         ServerInstance->WriteOpers("*** DNSBL(#%d): empty reason, using defaults",i);
 241                                         e->reason = "Your IP has been blacklisted.";
 242                                 }
 243
 244                                 /* add it, all is ok */
 245                                 DNSBLConfEntries.push_back(e);
 246                                 continue;
 247                         }
 248
 249                         /* delete and drop it, error somewhere */
 250                         delete e;
 251                 }
 252
 253                 delete MyConf;
 254         }
 255
 256         virtual void OnRehash(userrec* user, const std::string &parameter)
 257         {
 258                 ReadConf();
 259         }
 260
 261         /*
 262          * We will check each user that connects *locally* (userrec::fd>0)
 263          */
 264         virtual int OnUserRegister(userrec* user)
 265         {
 266                 if (IS_LOCAL(user))
 267                 {
 268                         /* following code taken from bopm, reverses an IP address. */
 269                         struct in_addr in;
 270                         unsigned char a, b, c, d;
 271                         char reversedipbuf[128];
 272                         std::string reversedip;
 273                         bool success = false;
 274
 275                         if (!inet_aton(user->GetIPString(), &in))
 276                         {
 277 #ifdef IPV6
 278                                 /* We could have an ipv6 address here */
 279                                 std::string x = user->GetIPString();
 280                                 /* Is it a 4in6 address? (Compensate for this kernel kludge that people love) */
 281                                 if (x.find("0::ffff:") == x.begin())
 282                                 {
 283                                         x.erase(x.begin(), x.begin() + 8);
 284                                         if (inet_aton(x.c_str(), &in))
 285                                                 success = true;
 286                                 }
 287 #endif
 288                         }
 289                         else
 290                         {
 291                                 success = true;
 292                         }
 293
 294                         if (!success)
 295                                 return 0;
 296
 297                         d = (unsigned char) (in.s_addr >> 24) & 0xFF;
 298                         c = (unsigned char) (in.s_addr >> 16) & 0xFF;
 299                         b = (unsigned char) (in.s_addr >> 8) & 0xFF;
 300                         a = (unsigned char) in.s_addr & 0xFF;
 301
 302                         snprintf(reversedipbuf, 128, "%d.%d.%d.%d", d, c, b, a);
 303                         reversedip = std::string(reversedipbuf);
 304
 305                         // For each DNSBL, we will run through this lookup
 306                         for (std::vector<DNSBLConfEntry *>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 307                         {
 308                                 // Fill hostname with a dnsbl style host (d.c.b.a.domain.tld)
 309                                 std::string hostname = reversedip + "." + (*i)->domain;
 310
 311                                 /* now we'd need to fire off lookups for `hostname'. */
 312                                 bool cached;
 313                                 DNSBLResolver *r = new DNSBLResolver(this, ServerInstance, hostname, user, user->GetFd(), *i, cached);
 314                                 ServerInstance->AddResolver(r, cached);
 315                         }
 316                 }
 317
 318                 /* don't do anything with this hot potato */
 319                 return 0;
 320         }
 321 };
 322
 323 // stuff down here is the module-factory stuff.
 324
 325 class ModuleDNSBLFactory : public ModuleFactory
 326 {
 327  public:
 328         ModuleDNSBLFactory()
 329         {
 330         }
 331
 332         ~ModuleDNSBLFactory()
 333         {
 334         }
 335
 336         virtual Module *CreateModule(InspIRCd *Me)
 337         {
 338                 return new ModuleDNSBL(Me);
 339         }
 340
 341 };
 342
 343
 344 extern "C" void * init_module( void )
 345 {
 346         return new ModuleDNSBLFactory;
 347 }