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                                         while (int pos = reason.find("%ip%") != std::string::npos)
  99                                         {
 100                                                 reason.replace(pos, 4, them->GetIPString());
 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                                                         them->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                 this just means they don't appear in the respective dnsbl
 142                 if ((them) && (them == ServerInstance->SE->GetRef(theirfd)))
 143                 {
 144                 }
 145                 */
 146                 /* Check the user still exists */
 147                 if ((them) && (them == ServerInstance->SE->GetRef(theirfd)))
 148                 {
 149                         ServerInstance->Log(DEBUG, "m_dnsbl:  %s got an error while resolving for dnsbl %s", them->nick, ConfEntry->name.c_str());
 150                 }
 151         }
 152
 153         virtual ~DNSBLResolver()
 154         {
 155         }
 156 };
 157
 158 class ModuleDNSBL : public Module
 159 {
 160  private:
 161         std::vector<DNSBLConfEntry *> DNSBLConfEntries;
 162
 163         /*
 164          *      Convert a string to EnumBanaction
 165          */
 166         DNSBLConfEntry::EnumBanaction str2banaction(const std::string &action)
 167         {
 168                 if(action.compare("KILL")==0)
 169                         return DNSBLConfEntry::I_KILL;
 170                 if(action.compare("KLINE")==0)
 171                         return DNSBLConfEntry::I_KLINE;
 172                 if(action.compare("ZLINE")==0)
 173                         return DNSBLConfEntry::I_ZLINE;
 174                 if(action.compare("GLINE")==0)
 175                         return DNSBLConfEntry::I_GLINE;
 176
 177                 return DNSBLConfEntry::I_UNKNOWN;
 178         }
 179  public:
 180         ModuleDNSBL(InspIRCd *Me) : Module::Module(Me)
 181         {
 182                 ReadConf();
 183         }
 184
 185         virtual ~ModuleDNSBL()
 186         {
 187         }
 188
 189         virtual Version GetVersion()
 190         {
 191                 return Version(2, 0, 0, 0, 0, API_VERSION);
 192         }
 193
 194         void Implements(char* List)
 195         {
 196                 List[I_OnRehash] = List[I_OnUserRegister] = 1;
 197         }
 198
 199         /*
 200          * Fill our conf vector with data
 201          */
 202         virtual void ReadConf()
 203         {
 204                 ConfigReader *MyConf = new ConfigReader(ServerInstance);
 205                 DNSBLConfEntries.clear();
 206
 207                 for (int i=0; i< MyConf->Enumerate("dnsbl"); i++)
 208                 {
 209                         DNSBLConfEntry *e = new DNSBLConfEntry();
 210
 211                         e->name = MyConf->ReadValue("dnsbl", "name", i);
 212                         e->reason = MyConf->ReadValue("dnsbl", "reason", i);
 213                         e->domain = MyConf->ReadValue("dnsbl", "domain", i);
 214                         e->banaction = str2banaction(MyConf->ReadValue("dnsbl", "action", i));
 215                         e->duration = ServerInstance->Duration(MyConf->ReadValue("dnsbl", "duration", i).c_str());
 216                         e->bitmask = MyConf->ReadInteger("dnsbl", "bitmask", i, false);
 217
 218                         /* yeah, logic here is a little messy */
 219                         if (e->bitmask <= 0)
 220                         {
 221                                 ServerInstance->WriteOpers("*** DNSBL(#%d): invalid bitmask",i);
 222                         }
 223                         else if (e->name == "")
 224                         {
 225                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid name",i);
 226                         }
 227                         else if (e->domain == "")
 228                         {
 229                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid domain",i);
 230                         }
 231                         else if (e->banaction == DNSBLConfEntry::I_UNKNOWN)
 232                         {
 233                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid banaction", i);
 234                         }
 235                         else
 236                         {
 237                                 if (e->reason == "")
 238                                 {
 239                                         ServerInstance->WriteOpers("*** DNSBL(#%d): empty reason, using defaults",i);
 240                                         e->reason = "Your IP has been blacklisted.";
 241                                 }
 242
 243                                 /* add it, all is ok */
 244                                 DNSBLConfEntries.push_back(e);
 245                                 delete MyConf;
 246                                 continue;
 247                         }
 248
 249                         /* delete and drop it, error somewhere */
 250                         delete e;
 251                 }
 252
 253                 delete MyConf;
 254         }
 255
 256
 257         virtual void OnRehash(const std::string &parameter)
 258         {
 259                 ReadConf();
 260         }
 261
 262         /*
 263          * We will check each user that connects *locally* (userrec::fd>0)
 264          */
 265         virtual int OnUserRegister(userrec* user)
 266         {
 267                 if (IS_LOCAL(user))
 268                 {
 269                         /* following code taken from bopm, reverses an IP address. */
 270                         struct in_addr in;
 271                         unsigned char a, b, c, d;
 272                         char reversedipbuf[128];
 273                         std::string reversedip;
 274
 275                         if (!inet_aton(user->GetIPString(), &in))
 276                         {
 277                                 ServerInstance->WriteOpers("Invalid IP address in m_dnsbl! Bailing check");
 278                                 return 0;
 279                         }
 280
 281                         d = (unsigned char) (in.s_addr >> 24) & 0xFF;
 282                         c = (unsigned char) (in.s_addr >> 16) & 0xFF;
 283                         b = (unsigned char) (in.s_addr >> 8) & 0xFF;
 284                         a = (unsigned char) in.s_addr & 0xFF;
 285
 286                         snprintf(reversedipbuf, 128, "%d.%d.%d.%d", d, c, b, a);
 287                         reversedip = std::string(reversedipbuf);
 288
 289 /*
 290         this is satmd's old code
 291                         std::string reversedip;
 292                         std::string userip = user->GetIPString();
 293                         std::string tempip = userip;
 294
 295                         // reversedip will created in there
 296                         while (tempip.length()>0)
 297                         {
 298                                 unsigned int lastdot=tempip.rfind(".");
 299                                 if (lastdot == std::string::npos)
 300                                 {
 301                                         reversedip+=tempip;
 302                                         tempip.clear();
 303                                 }
 304                                 else
 305                                 {
 306                                         reversedip += tempip.substr(lastdot+1,tempip.length()-lastdot+1);
 307                                         reversedip += ".";
 308                                         tempip.resize(lastdot);
 309                                 }
 310                         }
 311 */
 312
 313                         // For each DNSBL, we will run through this lookup
 314                         for (std::vector<DNSBLConfEntry *>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 315                         {
 316                                 // Fill hostname with a dnsbl style host (d.c.b.a.domain.tld)
 317                                 std::string hostname=reversedip+"."+ (*i)->domain;
 318
 319                                 ServerInstance->Log(DEBUG, "m_dnsbl: sending %s for resolution", hostname.c_str());
 320
 321                                 /* now we'd need to fire off lookups for `hostname'. */
 322                                 DNSBLResolver *r = new DNSBLResolver(this, ServerInstance, hostname, user, user->GetFd(), *i);
 323                                 ServerInstance->AddResolver(r);
 324                         }
 325                 }
 326
 327                 /* don't do anything with this hot potato */
 328                 return 0;
 329         }
 330 };
 331
 332 // stuff down here is the module-factory stuff.
 333
 334 class ModuleDNSBLFactory : public ModuleFactory
 335 {
 336  public:
 337         ModuleDNSBLFactory()
 338         {
 339         }
 340
 341         ~ModuleDNSBLFactory()
 342         {
 343         }
 344
 345         virtual Module *CreateModule(InspIRCd *Me)
 346         {
 347                 return new ModuleDNSBL(Me);
 348         }
 349
 350 };
 351
 352
 353 extern "C" void * init_module( void )
 354 {
 355         return new ModuleDNSBLFactory;
 356 }
 357