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                 ~DNSBLConfEntry() { }
  38 };
  39
  40
  41 /** Resolver for CGI:IRC hostnames encoded in ident/GECOS
  42  */
  43 class DNSBLResolver : public Resolver
  44 {
  45         int theirfd;
  46         userrec* them;
  47         DNSBLConfEntry *ConfEntry;
  48
  49     public:
  50         DNSBLResolver(Module *me, InspIRCd *ServerInstance, const std::string &hostname, userrec* u, int userfd, DNSBLConfEntry *conf, bool &cached)
  51                 : Resolver(ServerInstance, hostname, DNS_QUERY_A, cached, me)
  52         {
  53                 theirfd = userfd;
  54                 them = u;
  55                 ConfEntry = conf;
  56         }
  57
  58         virtual void OnLookupComplete(const std::string &result, unsigned int ttl, bool cached)
  59         {
  60                 /* Check the user still exists */
  61                 if ((them) && (them == ServerInstance->SE->GetRef(theirfd)))
  62                 {
  63                         // Now we calculate the bitmask: 256*(256*(256*a+b)+c)+d
  64                         if(result.length())
  65                         {
  66                                 unsigned int bitmask=0;
  67                                 in_addr resultip;
  68
  69                                 /* Convert the result to an in_addr (we can gaurantee we got ipv4)
  70                                  * Whoever did the loop that was here before, I AM CONFISCATING
  71                                  * YOUR CRACKPIPE. you know who you are. -- Brain
  72                                  */
  73                                 inet_aton(result.c_str(), &resultip);
  74                                 bitmask = resultip.s_addr >> 24; /* Last octet (network byte order */
  75
  76                                 bitmask &= ConfEntry->bitmask;
  77
  78                                 if (bitmask != 0)
  79                                 {
  80                                         std::string reason = ConfEntry->reason;
  81                                         std::string::size_type x = reason.find("%ip%");
  82                                         while (x != std::string::npos)
  83                                         {
  84                                                 reason.erase(x, 4);
  85                                                 reason.insert(x, them->GetIPString());
  86                                                 x = reason.find("%ip%");
  87                                         }
  88
  89                                         ServerInstance->WriteOpers("*** Connecting user %s detected as being on a DNS blacklist (%s) with result %d", them->GetFullRealHost(), ConfEntry->name.c_str(), bitmask);
  90
  91                                         switch (ConfEntry->banaction)
  92                                         {
  93                                                 case DNSBLConfEntry::I_KILL:
  94                                                 {
  95                                                         userrec::QuitUser(ServerInstance, them, std::string("Killed (") + reason + ")");
  96                                                         break;
  97                                                 }
  98                                                 case DNSBLConfEntry::I_KLINE:
  99                                                 {
 100                                                         ServerInstance->AddKLine(ConfEntry->duration, ServerInstance->Config->ServerName, reason, std::string("*@") + them->GetIPString());
 101                                                         FOREACH_MOD(I_OnAddKLine,OnAddKLine(ConfEntry->duration, NULL, reason, std::string("*@") + them->GetIPString()));
 102                                                         break;
 103                                                 }
 104                                                 case DNSBLConfEntry::I_GLINE:
 105                                                 {
 106                                                         ServerInstance->AddGLine(ConfEntry->duration, ServerInstance->Config->ServerName, reason, std::string("*@") + them->GetIPString());
 107                                                         FOREACH_MOD(I_OnAddGLine,OnAddGLine(ConfEntry->duration, NULL, reason, std::string("*@") + them->GetIPString()));
 108                                                         break;
 109                                                 }
 110                                                 case DNSBLConfEntry::I_ZLINE:
 111                                                 {
 112                                                         ServerInstance->AddZLine(ConfEntry->duration, ServerInstance->Config->ServerName, reason, them->GetIPString());
 113                                                         FOREACH_MOD(I_OnAddZLine,OnAddZLine(ConfEntry->duration, NULL, reason, them->GetIPString()));
 114                                                         break;
 115                                                 }
 116                                                 case DNSBLConfEntry::I_UNKNOWN:
 117                                                 {
 118                                                         break;
 119                                                 }
 120                                                 break;
 121                                         }
 122                                 }
 123                         }
 124                 }
 125         }
 126
 127         virtual void OnError(ResolverError e, const std::string &errormessage)
 128         {
 129         }
 130
 131         virtual ~DNSBLResolver()
 132         {
 133         }
 134 };
 135
 136 class ModuleDNSBL : public Module
 137 {
 138  private:
 139         std::vector<DNSBLConfEntry *> DNSBLConfEntries;
 140
 141         /*
 142          *      Convert a string to EnumBanaction
 143          */
 144         DNSBLConfEntry::EnumBanaction str2banaction(const std::string &action)
 145         {
 146                 if(action.compare("KILL")==0)
 147                         return DNSBLConfEntry::I_KILL;
 148                 if(action.compare("KLINE")==0)
 149                         return DNSBLConfEntry::I_KLINE;
 150                 if(action.compare("ZLINE")==0)
 151                         return DNSBLConfEntry::I_ZLINE;
 152                 if(action.compare("GLINE")==0)
 153                         return DNSBLConfEntry::I_GLINE;
 154
 155                 return DNSBLConfEntry::I_UNKNOWN;
 156         }
 157  public:
 158         ModuleDNSBL(InspIRCd *Me) : Module::Module(Me)
 159         {
 160                 ReadConf();
 161         }
 162
 163         virtual ~ModuleDNSBL()
 164         {
 165                 ClearEntries();
 166         }
 167
 168         virtual Version GetVersion()
 169         {
 170                 return Version(2, 0, 0, 1, VF_VENDOR, API_VERSION);
 171         }
 172
 173         void Implements(char* List)
 174         {
 175                 List[I_OnRehash] = List[I_OnUserRegister] = 1;
 176         }
 177
 178         /** Clear entries and free the mem it was using
 179          */
 180         void ClearEntries()
 181         {
 182                 std::vector<DNSBLConfEntry *>::iterator i;
 183                 for (std::vector<DNSBLConfEntry *>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 184                         delete *i;
 185                 DNSBLConfEntries.clear();
 186         }
 187
 188         /** Fill our conf vector with data
 189          */
 190         virtual void ReadConf()
 191         {
 192                 ConfigReader *MyConf = new ConfigReader(ServerInstance);
 193                 ClearEntries();
 194
 195                 for (int i=0; i< MyConf->Enumerate("dnsbl"); i++)
 196                 {
 197                         DNSBLConfEntry *e = new DNSBLConfEntry();
 198
 199                         e->name = MyConf->ReadValue("dnsbl", "name", i);
 200                         e->reason = MyConf->ReadValue("dnsbl", "reason", i);
 201                         e->domain = MyConf->ReadValue("dnsbl", "domain", i);
 202                         e->banaction = str2banaction(MyConf->ReadValue("dnsbl", "action", i));
 203                         e->duration = ServerInstance->Duration(MyConf->ReadValue("dnsbl", "duration", i).c_str());
 204                         e->bitmask = MyConf->ReadInteger("dnsbl", "bitmask", i, false);
 205
 206                         /* yeah, logic here is a little messy */
 207                         if (e->bitmask <= 0)
 208                         {
 209                                 ServerInstance->WriteOpers("*** DNSBL(#%d): invalid bitmask",i);
 210                         }
 211                         else if (e->name == "")
 212                         {
 213                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid name",i);
 214                         }
 215                         else if (e->domain == "")
 216                         {
 217                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid domain",i);
 218                         }
 219                         else if (e->banaction == DNSBLConfEntry::I_UNKNOWN)
 220                         {
 221                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid banaction", i);
 222                         }
 223                         else
 224                         {
 225                                 if (e->reason == "")
 226                                 {
 227                                         ServerInstance->WriteOpers("*** DNSBL(#%d): empty reason, using defaults",i);
 228                                         e->reason = "Your IP has been blacklisted.";
 229                                 }
 230
 231                                 /* add it, all is ok */
 232                                 DNSBLConfEntries.push_back(e);
 233                                 continue;
 234                         }
 235
 236                         /* delete and drop it, error somewhere */
 237                         delete e;
 238                 }
 239
 240                 delete MyConf;
 241         }
 242
 243         virtual void OnRehash(userrec* user, const std::string &parameter)
 244         {
 245                 ReadConf();
 246         }
 247
 248         /*
 249          * We will check each user that connects *locally* (userrec::fd>0)
 250          */
 251         virtual int OnUserRegister(userrec* user)
 252         {
 253                 if (IS_LOCAL(user))
 254                 {
 255                         /* following code taken from bopm, reverses an IP address. */
 256                         struct in_addr in;
 257                         unsigned char a, b, c, d;
 258                         char reversedipbuf[128];
 259                         std::string reversedip;
 260                         bool success = false;
 261
 262                         if (!inet_aton(user->GetIPString(), &in))
 263                         {
 264 #ifdef IPV6
 265                                 /* We could have an ipv6 address here */
 266                                 std::string x = user->GetIPString();
 267                                 /* Is it a 4in6 address? (Compensate for this kernel kludge that people love) */
 268                                 if (x.find("0::ffff:") == 0)
 269                                 {
 270                                         x.erase(x.begin(), x.begin() + 8);
 271                                         if (inet_aton(x.c_str(), &in))
 272                                                 success = true;
 273                                 }
 274 #endif
 275                         }
 276                         else
 277                         {
 278                                 success = true;
 279                         }
 280
 281                         if (!success)
 282                                 return 0;
 283
 284                         d = (unsigned char) (in.s_addr >> 24) & 0xFF;
 285                         c = (unsigned char) (in.s_addr >> 16) & 0xFF;
 286                         b = (unsigned char) (in.s_addr >> 8) & 0xFF;
 287                         a = (unsigned char) in.s_addr & 0xFF;
 288
 289                         snprintf(reversedipbuf, 128, "%d.%d.%d.%d", d, c, b, a);
 290                         reversedip = std::string(reversedipbuf);
 291
 292                         // For each DNSBL, we will run through this lookup
 293                         for (std::vector<DNSBLConfEntry *>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 294                         {
 295                                 // Fill hostname with a dnsbl style host (d.c.b.a.domain.tld)
 296                                 std::string hostname = reversedip + "." + (*i)->domain;
 297
 298                                 /* now we'd need to fire off lookups for `hostname'. */
 299                                 bool cached;
 300                                 DNSBLResolver *r = new DNSBLResolver(this, ServerInstance, hostname, user, user->GetFd(), *i, cached);
 301                                 ServerInstance->AddResolver(r, cached);
 302                         }
 303                 }
 304
 305                 /* don't do anything with this hot potato */
 306                 return 0;
 307         }
 308 };
 309
 310 // stuff down here is the module-factory stuff.
 311
 312 class ModuleDNSBLFactory : public ModuleFactory
 313 {
 314  public:
 315         ModuleDNSBLFactory()
 316         {
 317         }
 318
 319         ~ModuleDNSBLFactory()
 320         {
 321         }
 322
 323         virtual Module *CreateModule(InspIRCd *Me)
 324         {
 325                 return new ModuleDNSBL(Me);
 326         }
 327
 328 };
 329
 330
 331 extern "C" void * init_module( void )
 332 {
 333         return new ModuleDNSBLFactory;
 334 }