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 "inspircd.h"
  15 #include "xline.h"
  16 #include "dns.h"
  17 #include "users.h"
  18 #include "channels.h"
  19 #include "modules.h"
  20
  21 #ifndef WINDOWS
  22 #include <sys/types.h>
  23 #include <sys/socket.h>
  24 #include <netinet/in.h>
  25 #include <arpa/inet.h>
  26 #include <stdint.h>
  27 #endif
  28
  29 /* $ModDesc: Provides handling of DNS blacklists */
  30
  31 /* Class holding data for a single entry */
  32 class DNSBLConfEntry
  33 {
  34         public:
  35                 enum EnumBanaction { I_UNKNOWN, I_KILL, I_ZLINE, I_KLINE, I_GLINE };
  36                 std::string name, domain, reason;
  37                 EnumBanaction banaction;
  38                 long duration;
  39                 int bitmask;
  40                 unsigned long stats_hits, stats_misses;
  41                 DNSBLConfEntry(): duration(86400),bitmask(0),stats_hits(0), stats_misses(0) {}
  42                 ~DNSBLConfEntry() { }
  43 };
  44
  45
  46 /** Resolver for CGI:IRC hostnames encoded in ident/GECOS
  47  */
  48 class DNSBLResolver : public Resolver
  49 {
  50         int theirfd;
  51         userrec* them;
  52         DNSBLConfEntry *ConfEntry;
  53
  54     public:
  55         DNSBLResolver(Module *me, InspIRCd *ServerInstance, const std::string &hostname, userrec* u, int userfd, DNSBLConfEntry *conf, bool &cached)
  56                 : Resolver(ServerInstance, hostname, DNS_QUERY_A, cached, me)
  57         {
  58                 theirfd = userfd;
  59                 them = u;
  60                 ConfEntry = conf;
  61         }
  62
  63         virtual void OnLookupComplete(const std::string &result, unsigned int ttl, bool cached)
  64         {
  65                 /* Check the user still exists */
  66                 if ((them) && (them == ServerInstance->SE->GetRef(theirfd)))
  67                 {
  68                         // Now we calculate the bitmask: 256*(256*(256*a+b)+c)+d
  69                         if(result.length())
  70                         {
  71                                 unsigned int bitmask = 0;
  72                                 bool show = false;
  73                                 in_addr resultip;
  74
  75                                 /* Convert the result to an in_addr (we can gaurantee we got ipv4)
  76                                  * Whoever did the loop that was here before, I AM CONFISCATING
  77                                  * YOUR CRACKPIPE. you know who you are. -- Brain
  78                                  */
  79                                 inet_aton(result.c_str(), &resultip);
  80                                 bitmask = resultip.s_addr >> 24; /* Last octet (network byte order */
  81
  82                                 bitmask &= ConfEntry->bitmask;
  83
  84                                 if (bitmask != 0)
  85                                 {
  86                                         std::string reason = ConfEntry->reason;
  87                                         std::string::size_type x = reason.find("%ip%");
  88                                         while (x != std::string::npos)
  89                                         {
  90                                                 reason.erase(x, 4);
  91                                                 reason.insert(x, them->GetIPString());
  92                                                 x = reason.find("%ip%");
  93                                         }
  94
  95                                         ConfEntry->stats_hits++;
  96
  97                                         switch (ConfEntry->banaction)
  98                                         {
  99                                                 case DNSBLConfEntry::I_KILL:
 100                                                 {
 101                                                         userrec::QuitUser(ServerInstance, them, std::string("Killed (") + reason + ")");
 102                                                         break;
 103                                                 }
 104                                                 case DNSBLConfEntry::I_KLINE:
 105                                                 {
 106                                                         std::string ban = std::string("*@") + them->GetIPString();
 107                                                         show = ServerInstance->XLines->add_kline(ConfEntry->duration, ServerInstance->Config->ServerName, reason.c_str(), ban.c_str());
 108                                                         FOREACH_MOD(I_OnAddKLine,OnAddKLine(ConfEntry->duration, NULL, reason, ban));
 109                                                         break;
 110                                                 }
 111                                                 case DNSBLConfEntry::I_GLINE:
 112                                                 {
 113                                                         std::string ban = std::string("*@") + them->GetIPString();
 114                                                         show = ServerInstance->XLines->add_gline(ConfEntry->duration, ServerInstance->Config->ServerName, reason.c_str(), ban.c_str());
 115                                                         FOREACH_MOD(I_OnAddGLine,OnAddGLine(ConfEntry->duration, NULL, reason, ban));
 116                                                         break;
 117                                                 }
 118                                                 case DNSBLConfEntry::I_ZLINE:
 119                                                 {
 120                                                         show = ServerInstance->XLines->add_zline(ConfEntry->duration, ServerInstance->Config->ServerName, reason.c_str(), them->GetIPString());
 121                                                         FOREACH_MOD(I_OnAddZLine,OnAddZLine(ConfEntry->duration, NULL, reason, them->GetIPString()));
 122                                                         break;
 123                                                 }
 124                                                 case DNSBLConfEntry::I_UNKNOWN:
 125                                                 {
 126                                                         break;
 127                                                 }
 128                                                 break;
 129                                         }
 130
 131                                         if (show)
 132                                                 ServerInstance->WriteOpers("*** Connecting user %s detected as being on a DNS blacklist (%s) with result %d", them->GetFullRealHost(), ConfEntry->name.c_str(), bitmask);
 133                                 }
 134                                 else
 135                                         ConfEntry->stats_misses++;
 136                         }
 137                         else
 138                                 ConfEntry->stats_misses++;
 139                 }
 140         }
 141
 142         virtual void OnError(ResolverError e, const std::string &errormessage)
 143         {
 144         }
 145
 146         virtual ~DNSBLResolver()
 147         {
 148         }
 149 };
 150
 151 class ModuleDNSBL : public Module
 152 {
 153  private:
 154         std::vector<DNSBLConfEntry *> DNSBLConfEntries;
 155
 156         /*
 157          *      Convert a string to EnumBanaction
 158          */
 159         DNSBLConfEntry::EnumBanaction str2banaction(const std::string &action)
 160         {
 161                 if(action.compare("KILL")==0)
 162                         return DNSBLConfEntry::I_KILL;
 163                 if(action.compare("KLINE")==0)
 164                         return DNSBLConfEntry::I_KLINE;
 165                 if(action.compare("ZLINE")==0)
 166                         return DNSBLConfEntry::I_ZLINE;
 167                 if(action.compare("GLINE")==0)
 168                         return DNSBLConfEntry::I_GLINE;
 169
 170                 return DNSBLConfEntry::I_UNKNOWN;
 171         }
 172  public:
 173         ModuleDNSBL(InspIRCd *Me) : Module(Me)
 174         {
 175                 ReadConf();
 176         }
 177
 178         virtual ~ModuleDNSBL()
 179         {
 180                 ClearEntries();
 181         }
 182
 183         virtual Version GetVersion()
 184         {
 185                 return Version(2, 0, 0, 1, VF_VENDOR, API_VERSION);
 186         }
 187
 188         void Implements(char* List)
 189         {
 190                 List[I_OnRehash] = List[I_OnUserRegister] = List[I_OnStats] = 1;
 191         }
 192
 193         /** Clear entries and free the mem it was using
 194          */
 195         void ClearEntries()
 196         {
 197                 std::vector<DNSBLConfEntry *>::iterator i;
 198                 for (std::vector<DNSBLConfEntry *>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 199                         delete *i;
 200                 DNSBLConfEntries.clear();
 201         }
 202
 203         /** Fill our conf vector with data
 204          */
 205         virtual void ReadConf()
 206         {
 207                 ConfigReader *MyConf = new ConfigReader(ServerInstance);
 208                 ClearEntries();
 209
 210                 for (int i=0; i< MyConf->Enumerate("dnsbl"); i++)
 211                 {
 212                         DNSBLConfEntry *e = new DNSBLConfEntry();
 213
 214                         e->name = MyConf->ReadValue("dnsbl", "name", i);
 215                         e->reason = MyConf->ReadValue("dnsbl", "reason", i);
 216                         e->domain = MyConf->ReadValue("dnsbl", "domain", i);
 217                         e->banaction = str2banaction(MyConf->ReadValue("dnsbl", "action", i));
 218                         e->duration = ServerInstance->Duration(MyConf->ReadValue("dnsbl", "duration", i).c_str());
 219                         e->bitmask = MyConf->ReadInteger("dnsbl", "bitmask", i, false);
 220
 221                         /* yeah, logic here is a little messy */
 222                         if (e->bitmask <= 0)
 223                         {
 224                                 ServerInstance->WriteOpers("*** DNSBL(#%d): invalid bitmask",i);
 225                         }
 226                         else if (e->name == "")
 227                         {
 228                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid name",i);
 229                         }
 230                         else if (e->domain == "")
 231                         {
 232                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid domain",i);
 233                         }
 234                         else if (e->banaction == DNSBLConfEntry::I_UNKNOWN)
 235                         {
 236                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid banaction", i);
 237                         }
 238                         else
 239                         {
 240                                 if (e->reason == "")
 241                                 {
 242                                         ServerInstance->WriteOpers("*** DNSBL(#%d): empty reason, using defaults",i);
 243                                         e->reason = "Your IP has been blacklisted.";
 244                                 }
 245
 246                                 /* add it, all is ok */
 247                                 DNSBLConfEntries.push_back(e);
 248                                 continue;
 249                         }
 250
 251                         /* delete and drop it, error somewhere */
 252                         delete e;
 253                 }
 254
 255                 delete MyConf;
 256         }
 257
 258         virtual void OnRehash(userrec* user, const std::string &parameter)
 259         {
 260                 ReadConf();
 261         }
 262
 263         virtual int OnUserRegister(userrec* user)
 264         {
 265                 /* only do lookups on local users */
 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                         bool success = false;
 274
 275                         if (!inet_aton(user->GetIPString(), &in))
 276                         {
 277 #ifdef IPV6
 278                                 /* We could have an ipv6 address here */
 279                                 std::string x = user->GetIPString();
 280                                 /* Is it a 4in6 address? (Compensate for this kernel kludge that people love) */
 281                                 if (x.find("0::ffff:") == 0)
 282                                 {
 283                                         x.erase(x.begin(), x.begin() + 8);
 284                                         if (inet_aton(x.c_str(), &in))
 285                                                 success = true;
 286                                 }
 287 #endif
 288                         }
 289                         else
 290                         {
 291                                 success = true;
 292                         }
 293
 294                         if (!success)
 295                                 return 0;
 296
 297                         d = (unsigned char) (in.s_addr >> 24) & 0xFF;
 298                         c = (unsigned char) (in.s_addr >> 16) & 0xFF;
 299                         b = (unsigned char) (in.s_addr >> 8) & 0xFF;
 300                         a = (unsigned char) in.s_addr & 0xFF;
 301
 302                         snprintf(reversedipbuf, 128, "%d.%d.%d.%d", d, c, b, a);
 303                         reversedip = std::string(reversedipbuf);
 304
 305                         // For each DNSBL, we will run through this lookup
 306                         for (std::vector<DNSBLConfEntry *>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 307                         {
 308                                 // Fill hostname with a dnsbl style host (d.c.b.a.domain.tld)
 309                                 std::string hostname = reversedip + "." + (*i)->domain;
 310
 311                                 /* now we'd need to fire off lookups for `hostname'. */
 312                                 bool cached;
 313                                 DNSBLResolver *r = new DNSBLResolver(this, ServerInstance, hostname, user, user->GetFd(), *i, cached);
 314                                 ServerInstance->AddResolver(r, cached);
 315                         }
 316                 }
 317
 318                 /* don't do anything with this hot potato */
 319                 return 0;
 320         }
 321
 322         virtual int OnStats(char symbol, userrec* user, string_list &results)
 323         {
 324                 if (symbol != 'd')
 325                         return 0;
 326
 327                 unsigned long total_hits = 0, total_misses = 0;
 328
 329                 for (std::vector<DNSBLConfEntry*>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 330                 {
 331                         total_hits += (*i)->stats_hits;
 332                         total_misses += (*i)->stats_misses;
 333
 334                         results.push_back(std::string(ServerInstance->Config->ServerName) + " 304 " + user->nick + " :DNSBLSTATS DNSbl \"" + (*i)->name + "\" had " +
 335                                         ConvToStr((*i)->stats_hits) + " hits and " + ConvToStr((*i)->stats_misses) + " misses");
 336                 }
 337
 338                 results.push_back(std::string(ServerInstance->Config->ServerName) + " 304 " + user->nick + " :DNSBLSTATS Total hits: " + ConvToStr(total_hits));
 339                 results.push_back(std::string(ServerInstance->Config->ServerName) + " 304 " + user->nick + " :DNSBLSTATS Total misses: " + ConvToStr(total_misses));
 340
 341                 return 0;
 342         }
 343 };
 344
 345 // stuff down here is the module-factory stuff.
 346
 347 class ModuleDNSBLFactory : public ModuleFactory
 348 {
 349  public:
 350         ModuleDNSBLFactory()
 351         {
 352         }
 353
 354         ~ModuleDNSBLFactory()
 355         {
 356         }
 357
 358         virtual Module *CreateModule(InspIRCd *Me)
 359         {
 360                 return new ModuleDNSBL(Me);
 361         }
 362
 363 };
 364
 365
 366 extern "C" DllExport void * init_module( void )
 367 {
 368         return new ModuleDNSBLFactory;
 369 }