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                                         unsigned int lastdot = tmp.rfind(".");
  75
  76                                         if (lastdot == std::string::npos)
  77                                         {
  78                                                 octet=tmp;
  79                                                 tmp.clear();
  80                                         }
  81                                         else
  82                                         {
  83                                                 octet=tmp.substr(lastdot+1,tmp.length()-lastdot+1);
  84                                                 tmp.resize(lastdot);
  85                                         }
  86
  87                                         bitmask += (256 ^ octetpos) * atoi(octet.c_str());
  88                                         octetpos += 1;
  89                                 }
  90
  91                                 bitmask &= ConfEntry->bitmask;
  92
  93                                 if (bitmask != 0)
  94                                 {
  95                                         std::string reason = ConfEntry->reason;
  96
  97                                         while (int pos = reason.find("%ip%") != std::string::npos)
  98                                         {
  99                                                 reason.replace(pos, 4, them->GetIPString());
 100                                         }
 101
 102                                         ServerInstance->WriteOpers("*** Connecting user %s detected as being on a DNS blacklist (%s) with result %d", them->GetFullRealHost(), ConfEntry->name.c_str(), bitmask);
 103
 104                                         switch (ConfEntry->banaction)
 105                                         {
 106                                                 case DNSBLConfEntry::I_KILL:
 107                                                 {
 108                                                         them->QuitUser(ServerInstance, them, std::string("Killed (") + reason + ")");
 109                                                         break;
 110                                                 }
 111                                                 case DNSBLConfEntry::I_KLINE:
 112                                                 {
 113                                                         ServerInstance->AddKLine(ConfEntry->duration, ServerInstance->Config->ServerName, reason, std::string("*@") + them->GetIPString());
 114                                                         break;
 115                                                 }
 116                                                 case DNSBLConfEntry::I_GLINE:
 117                                                 {
 118                                                         ServerInstance->AddGLine(ConfEntry->duration, ServerInstance->Config->ServerName, reason, std::string("*@") + them->GetIPString());
 119                                                         break;
 120                                                 }
 121                                                 case DNSBLConfEntry::I_ZLINE:
 122                                                 {
 123                                                         ServerInstance->AddZLine(ConfEntry->duration, ServerInstance->Config->ServerName, reason, them->GetIPString());
 124                                                         break;
 125                                                 }
 126                                                 case DNSBLConfEntry::I_UNKNOWN:
 127                                                 {
 128                                                         break;
 129                                                 }
 130                                                 break;
 131                                         }
 132                                 }
 133                         }
 134                 }
 135         }
 136
 137         virtual void OnError(ResolverError e, const std::string &errormessage)
 138         {
 139                 /*
 140                 this just means they don't appear in the respective dnsbl
 141                 if ((them) && (them == ServerInstance->SE->GetRef(theirfd)))
 142                 {
 143                 }
 144                 */
 145                 /* Check the user still exists */
 146                 if ((them) && (them == ServerInstance->SE->GetRef(theirfd)))
 147                 {
 148                         ServerInstance->Log(DEBUG, "m_dnsbl:  %s got an error while resolving for dnsbl %s", them->nick, ConfEntry->name.c_str());
 149                 }
 150         }
 151
 152         virtual ~DNSBLResolver()
 153         {
 154         }
 155 };
 156
 157 class ModuleDNSBL : public Module
 158 {
 159  private:
 160         std::vector<DNSBLConfEntry *> DNSBLConfEntries;
 161
 162         /*
 163          *      Convert a string to EnumBanaction
 164          */
 165         DNSBLConfEntry::EnumBanaction str2banaction(const std::string &action)
 166         {
 167                 if(action.compare("KILL")==0)
 168                         return DNSBLConfEntry::I_KILL;
 169                 if(action.compare("KLINE")==0)
 170                         return DNSBLConfEntry::I_KLINE;
 171                 if(action.compare("ZLINE")==0)
 172                         return DNSBLConfEntry::I_ZLINE;
 173                 if(action.compare("GLINE")==0)
 174                         return DNSBLConfEntry::I_GLINE;
 175
 176                 return DNSBLConfEntry::I_UNKNOWN;
 177         }
 178  public:
 179         ModuleDNSBL(InspIRCd *Me) : Module::Module(Me)
 180         {
 181                 ReadConf();
 182         }
 183
 184         virtual ~ModuleDNSBL()
 185         {
 186         }
 187
 188         virtual Version GetVersion()
 189         {
 190                 return Version(2, 0, 0, 0, 0, API_VERSION);
 191         }
 192
 193         void Implements(char* List)
 194         {
 195                 List[I_OnRehash] = List[I_OnUserRegister] = 1;
 196         }
 197
 198         /*
 199          * Fill our conf vector with data
 200          */
 201         virtual void ReadConf()
 202         {
 203                 ConfigReader *MyConf = new ConfigReader(ServerInstance);
 204                 DNSBLConfEntries.clear();
 205
 206                 for (int i=0; i< MyConf->Enumerate("dnsbl"); i++)
 207                 {
 208                         DNSBLConfEntry *e = new DNSBLConfEntry();
 209
 210                         e->name = MyConf->ReadValue("dnsbl", "name", i);
 211                         e->reason = MyConf->ReadValue("dnsbl", "reason", i);
 212                         e->domain = MyConf->ReadValue("dnsbl", "domain", i);
 213                         e->banaction = str2banaction(MyConf->ReadValue("dnsbl", "action", i));
 214                         e->duration = ServerInstance->Duration(MyConf->ReadValue("dnsbl", "duration", i).c_str());
 215                         e->bitmask = MyConf->ReadInteger("dnsbl", "bitmask", i, false);
 216
 217                         /* yeah, logic here is a little messy */
 218                         if (e->bitmask <= 0)
 219                         {
 220                                 ServerInstance->WriteOpers("*** DNSBL(#%d): invalid bitmask",i);
 221                         }
 222                         else if (e->name == "")
 223                         {
 224                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid name",i);
 225                         }
 226                         else if (e->domain == "")
 227                         {
 228                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid domain",i);
 229                         }
 230                         else if (e->banaction == DNSBLConfEntry::I_UNKNOWN)
 231                         {
 232                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid banaction", i);
 233                         }
 234                         else
 235                         {
 236                                 if (e->reason == "")
 237                                 {
 238                                         ServerInstance->WriteOpers("*** DNSBL(#%d): empty reason, using defaults",i);
 239                                         e->reason = "Your IP has been blacklisted.";
 240                                 }
 241
 242                                 /* add it, all is ok */
 243                                 DNSBLConfEntries.push_back(e);
 244                                 delete MyConf;
 245                                 continue;
 246                         }
 247
 248                         /* delete and drop it, error somewhere */
 249                         delete e;
 250                 }
 251
 252                 delete MyConf;
 253         }
 254
 255
 256         virtual void OnRehash(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
 274                         if (!inet_aton(user->GetIPString(), &in))
 275                         {
 276                                 ServerInstance->WriteOpers("Invalid IP address in m_dnsbl! Bailing check");
 277                                 return 0;
 278                         }
 279
 280                         d = (unsigned char) (in.s_addr >> 24) & 0xFF;
 281                         c = (unsigned char) (in.s_addr >> 16) & 0xFF;
 282                         b = (unsigned char) (in.s_addr >> 8) & 0xFF;
 283                         a = (unsigned char) in.s_addr & 0xFF;
 284
 285                         snprintf(reversedipbuf, 128, "%d.%d.%d.%d", d, c, b, a);
 286                         reversedip = std::string(reversedipbuf);
 287
 288 /*
 289         this is satmd's old code
 290                         std::string reversedip;
 291                         std::string userip = user->GetIPString();
 292                         std::string tempip = userip;
 293
 294                         // reversedip will created in there
 295                         while (tempip.length()>0)
 296                         {
 297                                 unsigned int lastdot=tempip.rfind(".");
 298                                 if (lastdot == std::string::npos)
 299                                 {
 300                                         reversedip+=tempip;
 301                                         tempip.clear();
 302                                 }
 303                                 else
 304                                 {
 305                                         reversedip += tempip.substr(lastdot+1,tempip.length()-lastdot+1);
 306                                         reversedip += ".";
 307                                         tempip.resize(lastdot);
 308                                 }
 309                         }
 310 */
 311
 312                         // For each DNSBL, we will run through this lookup
 313                         for (std::vector<DNSBLConfEntry *>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 314                         {
 315                                 // Fill hostname with a dnsbl style host (d.c.b.a.domain.tld)
 316                                 std::string hostname=reversedip+"."+ (*i)->domain;
 317
 318                                 ServerInstance->Log(DEBUG, "m_dnsbl: sending %s for resolution", hostname.c_str());
 319
 320                                 /* now we'd need to fire off lookups for `hostname'. */
 321                                 DNSBLResolver *r = new DNSBLResolver(this, ServerInstance, hostname, user, user->GetFd(), *i);
 322                                 ServerInstance->AddResolver(r);
 323                         }
 324                 }
 325
 326                 /* don't do anything with this hot potato */
 327                 return 0;
 328         }
 329 };
 330
 331 // stuff down here is the module-factory stuff.
 332
 333 class ModuleDNSBLFactory : public ModuleFactory
 334 {
 335  public:
 336         ModuleDNSBLFactory()
 337         {
 338         }
 339
 340         ~ModuleDNSBLFactory()
 341         {
 342         }
 343
 344         virtual Module *CreateModule(InspIRCd *Me)
 345         {
 346                 return new ModuleDNSBL(Me);
 347         }
 348
 349 };
 350
 351
 352 extern "C" void * init_module( void )
 353 {
 354         return new ModuleDNSBLFactory;
 355 }
 356