src/modules/m_dnsbl.cpp

   1 /*
   2  * Formerly written and maintained by satmd.
   3  * This version written and maintained by w00t.
   4  */
   5 #include <sys/types.h>
   6 #include <sys/socket.h>
   7 #include <netinet/in.h>
   8 #include <arpa/inet.h>
   9 #include <stdint.h>
  10 #include "inspircd.h"
  11 #include "dns.h"
  12 #include "users.h"
  13 #include "channels.h"
  14 #include "modules.h"
  15
  16 /* $ModDesc: Provides handling of DNS blacklists */
  17
  18 /* Class holding data for a single entry */
  19 class DNSBLConfEntry
  20 {
  21         public:
  22                 enum EnumBanaction { I_UNKNOWN, I_KILL, I_ZLINE, I_KLINE, I_GLINE };
  23                 std::string name, domain, reason;
  24                 EnumBanaction banaction;
  25                 long duration;
  26                 int bitmask;
  27                 DNSBLConfEntry(): duration(86400),bitmask(0) {}
  28 };
  29
  30
  31 /** Resolver for CGI:IRC hostnames encoded in ident/GECOS
  32  */
  33 class DNSBLResolver : public Resolver
  34 {
  35         int theirfd;
  36         userrec* them;
  37         DNSBLConfEntry *ConfEntry;
  38
  39     public:
  40         DNSBLResolver(Module *me, InspIRCd *ServerInstance, const std::string &hostname, userrec* u, int userfd, DNSBLConfEntry *conf)
  41                 : Resolver(ServerInstance, hostname, DNS_QUERY_A, me)
  42         {
  43                 theirfd = userfd;
  44                 them = u;
  45                 ConfEntry = conf;
  46         }
  47
  48         virtual void OnLookupComplete(const std::string &result)
  49         {
  50                 /* Check the user still exists */
  51                 if ((them) && (them == ServerInstance->SE->GetRef(theirfd)))
  52                 {
  53                         ServerInstance->Log(DEBUG, "m_dnsbl:  %s got a result from dnsbl %s", them->nick, ConfEntry->name.c_str());
  54
  55                         // Now we calculate the bitmask: 256*(256*(256*a+b)+c)+d
  56                         if(result.length())
  57                         {
  58                                 unsigned int bitmask=0;
  59                                 unsigned int octetpos=0;
  60                                 std::string tmp = result;
  61
  62                                 while(tmp.length()>0)
  63                                 {
  64                                         std::string octet;
  65                                         unsigned int lastdot = tmp.rfind(".");
  66
  67                                         if (lastdot == std::string::npos)
  68                                         {
  69                                                 octet=tmp;
  70                                                 tmp.clear();
  71                                         }
  72                                         else
  73                                         {
  74                                                 octet=tmp.substr(lastdot+1,tmp.length()-lastdot+1);
  75                                                 tmp.resize(lastdot);
  76                                         }
  77
  78                                         bitmask += (256 ^ octetpos) * atoi(octet.c_str());
  79                                         octetpos += 1;
  80                                 }
  81
  82                                 bitmask &= ConfEntry->bitmask;
  83
  84                                 if (bitmask != 0)
  85                                 {
  86                                         std::string reason = ConfEntry->reason;
  87
  88                                         while (int pos = reason.find("%ip%") != std::string::npos)
  89                                         {
  90                                                 reason.replace(pos, 4, them->GetIPString());
  91                                         }
  92
  93                                         ServerInstance->WriteOpers("*** Connecting user %s detected as being on a DNS blacklist (%s) with result %d", them->GetFullRealHost(), ConfEntry->name.c_str(), bitmask);
  94
  95                                         switch (ConfEntry->banaction)
  96                                         {
  97                                                 case DNSBLConfEntry::I_KILL:
  98                                                 {
  99                                                         them->QuitUser(ServerInstance, them, std::string("Killed (") + reason + ")");
 100                                                         break;
 101                                                 }
 102                                                 case DNSBLConfEntry::I_KLINE:
 103                                                 {
 104                                                         ServerInstance->AddKLine(ConfEntry->duration, ServerInstance->Config->ServerName, reason, std::string("*@") + them->GetIPString());
 105                                                         break;
 106                                                 }
 107                                                 case DNSBLConfEntry::I_GLINE:
 108                                                 {
 109                                                         ServerInstance->AddGLine(ConfEntry->duration, ServerInstance->Config->ServerName, reason, std::string("*@") + them->GetIPString());
 110                                                         break;
 111                                                 }
 112                                                 case DNSBLConfEntry::I_ZLINE:
 113                                                 {
 114                                                         ServerInstance->AddZLine(ConfEntry->duration, ServerInstance->Config->ServerName, reason, them->GetIPString());
 115                                                         break;
 116                                                 }
 117                                                 case DNSBLConfEntry::I_UNKNOWN:
 118                                                 {
 119                                                         break;
 120                                                 }
 121                                                 break;
 122                                         }
 123                                 }
 124                         }
 125                 }
 126         }
 127
 128         virtual void OnError(ResolverError e, const std::string &errormessage)
 129         {
 130                 /*
 131                 this just means they don't appear in the respective dnsbl
 132                 if ((them) && (them == ServerInstance->SE->GetRef(theirfd)))
 133                 {
 134                 }
 135                 */
 136                 /* Check the user still exists */
 137                 if ((them) && (them == ServerInstance->SE->GetRef(theirfd)))
 138                 {
 139                         ServerInstance->Log(DEBUG, "m_dnsbl:  %s got an error while resolving for dnsbl %s", them->nick, ConfEntry->name.c_str());
 140                 }
 141         }
 142
 143         virtual ~DNSBLResolver()
 144         {
 145         }
 146 };
 147
 148 class ModuleDNSBL : public Module
 149 {
 150  private:
 151         std::vector<DNSBLConfEntry *> DNSBLConfEntries;
 152
 153         /*
 154          *      Convert a string to EnumBanaction
 155          */
 156         DNSBLConfEntry::EnumBanaction str2banaction(const std::string &action)
 157         {
 158                 if(action.compare("KILL")==0)
 159                         return DNSBLConfEntry::I_KILL;
 160                 if(action.compare("KLINE")==0)
 161                         return DNSBLConfEntry::I_KLINE;
 162                 if(action.compare("ZLINE")==0)
 163                         return DNSBLConfEntry::I_ZLINE;
 164                 if(action.compare("GLINE")==0)
 165                         return DNSBLConfEntry::I_GLINE;
 166
 167                 return DNSBLConfEntry::I_UNKNOWN;
 168         }
 169  public:
 170         ModuleDNSBL(InspIRCd *Me) : Module::Module(Me)
 171         {
 172                 ReadConf();
 173         }
 174
 175         virtual ~ModuleDNSBL()
 176         {
 177         }
 178
 179         virtual Version GetVersion()
 180         {
 181                 return Version(2, 0, 0, 0, 0, API_VERSION);
 182         }
 183
 184         void Implements(char* List)
 185         {
 186                 List[I_OnRehash] = List[I_OnUserRegister] = 1;
 187         }
 188
 189         /*
 190          * Fill our conf vector with data
 191          */
 192         virtual void ReadConf()
 193         {
 194                 ConfigReader *MyConf = new ConfigReader(ServerInstance);
 195                 DNSBLConfEntries.clear();
 196
 197                 for (int i=0; i< MyConf->Enumerate("dnsbl"); i++)
 198                 {
 199                         DNSBLConfEntry *e = new DNSBLConfEntry();
 200
 201                         e->name = MyConf->ReadValue("dnsbl", "name", i);
 202                         e->reason = MyConf->ReadValue("dnsbl", "reason", i);
 203                         e->domain = MyConf->ReadValue("dnsbl", "domain", i);
 204                         e->banaction = str2banaction(MyConf->ReadValue("dnsbl", "action", i));
 205                         e->duration = ServerInstance->Duration(MyConf->ReadValue("dnsbl", "duration", i).c_str());
 206                         e->bitmask = MyConf->ReadInteger("dnsbl", "bitmask", i, false);
 207
 208                         /* yeah, logic here is a little messy */
 209                         if (e->bitmask <= 0)
 210                         {
 211                                 ServerInstance->WriteOpers("*** DNSBL(#%d): invalid bitmask",i);
 212                         }
 213                         else if (e->name == "")
 214                         {
 215                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid name",i);
 216                         }
 217                         else if (e->domain == "")
 218                         {
 219                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid domain",i);
 220                         }
 221                         else if (e->banaction == DNSBLConfEntry::I_UNKNOWN)
 222                         {
 223                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid banaction", i);
 224                         }
 225                         else
 226                         {
 227                                 if (e->reason == "")
 228                                 {
 229                                         ServerInstance->WriteOpers("*** DNSBL(#%d): empty reason, using defaults",i);
 230                                         e->reason = "Your IP has been blacklisted.";
 231                                 }
 232
 233                                 /* add it, all is ok */
 234                                 DNSBLConfEntries.push_back(e);
 235                                 delete MyConf;
 236                                 return;
 237                         }
 238
 239                         /* delete and drop it, error somewhere */
 240                         delete e;
 241                 }
 242
 243                 delete MyConf;
 244         }
 245
 246
 247         virtual void OnRehash(const std::string &parameter)
 248         {
 249                 ReadConf();
 250         }
 251
 252         /*
 253          * We will check each user that connects *locally* (userrec::fd>0)
 254          */
 255         virtual int OnUserRegister(userrec* user)
 256         {
 257                 if (IS_LOCAL(user))
 258                 {
 259                         /* following code taken from bopm, reverses an IP address. */
 260                         struct in_addr in;
 261                         unsigned char a, b, c, d;
 262                         char reversedipbuf[128];
 263                         std::string reversedip;
 264
 265                         if (!inet_aton(user->GetIPString(), &in))
 266                         {
 267                                 ServerInstance->WriteOpers("Invalid IP address in m_dnsbl! Bailing check");
 268                                 return 0;
 269                         }
 270
 271                         d = (unsigned char) (in.s_addr >> 24) & 0xFF;
 272                         c = (unsigned char) (in.s_addr >> 16) & 0xFF;
 273                         b = (unsigned char) (in.s_addr >> 8) & 0xFF;
 274                         a = (unsigned char) in.s_addr & 0xFF;
 275
 276                         snprintf(reversedipbuf, 128, "%d.%d.%d.%d", d, c, b, a);
 277                         reversedip = std::string(reversedipbuf);
 278
 279 /*
 280         this is satmd's old code
 281                         std::string reversedip;
 282                         std::string userip = user->GetIPString();
 283                         std::string tempip = userip;
 284
 285                         // reversedip will created in there
 286                         while (tempip.length()>0)
 287                         {
 288                                 unsigned int lastdot=tempip.rfind(".");
 289                                 if (lastdot == std::string::npos)
 290                                 {
 291                                         reversedip+=tempip;
 292                                         tempip.clear();
 293                                 }
 294                                 else
 295                                 {
 296                                         reversedip += tempip.substr(lastdot+1,tempip.length()-lastdot+1);
 297                                         reversedip += ".";
 298                                         tempip.resize(lastdot);
 299                                 }
 300                         }
 301 */
 302
 303                         // For each DNSBL, we will run through this lookup
 304                         for (std::vector<DNSBLConfEntry *>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 305                         {
 306                                 // Fill hostname with a dnsbl style host (d.c.b.a.domain.tld)
 307                                 std::string hostname=reversedip+"."+ (*i)->domain;
 308
 309                                 ServerInstance->Log(DEBUG, "m_dnsbl: sending %s for resolution", hostname.c_str());
 310
 311                                 /* now we'd need to fire off lookups for `hostname'. */
 312                                 DNSBLResolver *r = new DNSBLResolver(this, ServerInstance, hostname, user, user->GetFd(), *i);
 313                                 ServerInstance->AddResolver(r);
 314                         }
 315                 }
 316
 317                 /* don't do anything with this hot potato */
 318                 return 0;
 319         }
 320 };
 321
 322 // stuff down here is the module-factory stuff.
 323
 324 class ModuleDNSBLFactory : public ModuleFactory
 325 {
 326  public:
 327         ModuleDNSBLFactory()
 328         {
 329         }
 330
 331         ~ModuleDNSBLFactory()
 332         {
 333         }
 334
 335         virtual Module *CreateModule(InspIRCd *Me)
 336         {
 337                 return new ModuleDNSBL(Me);
 338         }
 339
 340 };
 341
 342
 343 extern "C" void * init_module( void )
 344 {
 345         return new ModuleDNSBLFactory;
 346 }
 347