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