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 "xline.h"
  21 #include "dns.h"
  22 #include "users.h"
  23 #include "channels.h"
  24 #include "modules.h"
  25
  26 /* $ModDesc: Provides handling of DNS blacklists */
  27
  28 /* Class holding data for a single entry */
  29 class DNSBLConfEntry
  30 {
  31         public:
  32                 enum EnumBanaction { I_UNKNOWN, I_KILL, I_ZLINE, I_KLINE, I_GLINE };
  33                 std::string name, domain, reason;
  34                 EnumBanaction banaction;
  35                 long duration;
  36                 int bitmask;
  37                 unsigned long stats_hits, stats_misses;
  38                 DNSBLConfEntry(): duration(86400),bitmask(0),stats_hits(0), stats_misses(0) {}
  39                 ~DNSBLConfEntry() { }
  40 };
  41
  42
  43 /** Resolver for CGI:IRC hostnames encoded in ident/GECOS
  44  */
  45 class DNSBLResolver : public Resolver
  46 {
  47         int theirfd;
  48         userrec* them;
  49         DNSBLConfEntry *ConfEntry;
  50
  51     public:
  52         DNSBLResolver(Module *me, InspIRCd *ServerInstance, const std::string &hostname, userrec* u, int userfd, DNSBLConfEntry *conf, bool &cached)
  53                 : Resolver(ServerInstance, hostname, DNS_QUERY_A, cached, me)
  54         {
  55                 theirfd = userfd;
  56                 them = u;
  57                 ConfEntry = conf;
  58         }
  59
  60         virtual void OnLookupComplete(const std::string &result, unsigned int ttl, bool cached)
  61         {
  62                 /* Check the user still exists */
  63                 if ((them) && (them == ServerInstance->SE->GetRef(theirfd)))
  64                 {
  65                         // Now we calculate the bitmask: 256*(256*(256*a+b)+c)+d
  66                         if(result.length())
  67                         {
  68                                 unsigned int bitmask = 0;
  69                                 bool show = false;
  70                                 in_addr resultip;
  71
  72                                 /* Convert the result to an in_addr (we can gaurantee we got ipv4)
  73                                  * Whoever did the loop that was here before, I AM CONFISCATING
  74                                  * YOUR CRACKPIPE. you know who you are. -- Brain
  75                                  */
  76                                 inet_aton(result.c_str(), &resultip);
  77                                 bitmask = resultip.s_addr >> 24; /* Last octet (network byte order */
  78
  79                                 bitmask &= ConfEntry->bitmask;
  80
  81                                 if (bitmask != 0)
  82                                 {
  83                                         std::string reason = ConfEntry->reason;
  84                                         std::string::size_type x = reason.find("%ip%");
  85                                         while (x != std::string::npos)
  86                                         {
  87                                                 reason.erase(x, 4);
  88                                                 reason.insert(x, them->GetIPString());
  89                                                 x = reason.find("%ip%");
  90                                         }
  91
  92                                         ConfEntry->stats_hits++;
  93
  94                                         switch (ConfEntry->banaction)
  95                                         {
  96                                                 case DNSBLConfEntry::I_KILL:
  97                                                 {
  98                                                         userrec::QuitUser(ServerInstance, them, std::string("Killed (") + reason + ")");
  99                                                         break;
 100                                                 }
 101                                                 case DNSBLConfEntry::I_KLINE:
 102                                                 {
 103                                                         std::string ban = std::string("*@") + them->GetIPString();
 104                                                         show = ServerInstance->XLines->add_kline(ConfEntry->duration, ServerInstance->Config->ServerName, reason.c_str(), ban.c_str());
 105                                                         FOREACH_MOD(I_OnAddKLine,OnAddKLine(ConfEntry->duration, NULL, reason, ban));
 106                                                         break;
 107                                                 }
 108                                                 case DNSBLConfEntry::I_GLINE:
 109                                                 {
 110                                                         std::string ban = std::string("*@") + them->GetIPString();
 111                                                         show = ServerInstance->XLines->add_gline(ConfEntry->duration, ServerInstance->Config->ServerName, reason.c_str(), ban.c_str());
 112                                                         FOREACH_MOD(I_OnAddGLine,OnAddGLine(ConfEntry->duration, NULL, reason, ban));
 113                                                         break;
 114                                                 }
 115                                                 case DNSBLConfEntry::I_ZLINE:
 116                                                 {
 117                                                         show = ServerInstance->XLines->add_zline(ConfEntry->duration, ServerInstance->Config->ServerName, reason.c_str(), them->GetIPString());
 118                                                         FOREACH_MOD(I_OnAddZLine,OnAddZLine(ConfEntry->duration, NULL, reason, them->GetIPString()));
 119                                                         break;
 120                                                 }
 121                                                 case DNSBLConfEntry::I_UNKNOWN:
 122                                                 {
 123                                                         break;
 124                                                 }
 125                                                 break;
 126                                         }
 127
 128                                         if (show)
 129                                                 ServerInstance->WriteOpers("*** Connecting user %s detected as being on a DNS blacklist (%s) with result %d", them->GetFullRealHost(), ConfEntry->name.c_str(), bitmask);
 130                                 }
 131                                 else
 132                                         ConfEntry->stats_misses++;
 133                         }
 134                         else
 135                                 ConfEntry->stats_misses++;
 136                 }
 137         }
 138
 139         virtual void OnError(ResolverError e, const std::string &errormessage)
 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                 ClearEntries();
 178         }
 179
 180         virtual Version GetVersion()
 181         {
 182                 return Version(2, 0, 0, 1, VF_VENDOR, API_VERSION);
 183         }
 184
 185         void Implements(char* List)
 186         {
 187                 List[I_OnRehash] = List[I_OnUserRegister] = List[I_OnStats] = 1;
 188         }
 189
 190         /** Clear entries and free the mem it was using
 191          */
 192         void ClearEntries()
 193         {
 194                 std::vector<DNSBLConfEntry *>::iterator i;
 195                 for (std::vector<DNSBLConfEntry *>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 196                         delete *i;
 197                 DNSBLConfEntries.clear();
 198         }
 199
 200         /** Fill our conf vector with data
 201          */
 202         virtual void ReadConf()
 203         {
 204                 ConfigReader *MyConf = new ConfigReader(ServerInstance);
 205                 ClearEntries();
 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                                 continue;
 246                         }
 247
 248                         /* delete and drop it, error somewhere */
 249                         delete e;
 250                 }
 251
 252                 delete MyConf;
 253         }
 254
 255         virtual void OnRehash(userrec* user, const std::string &parameter)
 256         {
 257                 ReadConf();
 258         }
 259
 260         /*
 261          * We will check each user that connects *locally* (userrec::fd>0)
 262          */
 263         virtual int OnUserRegister(userrec* user)
 264         {
 265                 if (IS_LOCAL(user))
 266                 {
 267                         /* following code taken from bopm, reverses an IP address. */
 268                         struct in_addr in;
 269                         unsigned char a, b, c, d;
 270                         char reversedipbuf[128];
 271                         std::string reversedip;
 272                         bool success = false;
 273
 274                         if (!inet_aton(user->GetIPString(), &in))
 275                         {
 276 #ifdef IPV6
 277                                 /* We could have an ipv6 address here */
 278                                 std::string x = user->GetIPString();
 279                                 /* Is it a 4in6 address? (Compensate for this kernel kludge that people love) */
 280                                 if (x.find("0::ffff:") == 0)
 281                                 {
 282                                         x.erase(x.begin(), x.begin() + 8);
 283                                         if (inet_aton(x.c_str(), &in))
 284                                                 success = true;
 285                                 }
 286 #endif
 287                         }
 288                         else
 289                         {
 290                                 success = true;
 291                         }
 292
 293                         if (!success)
 294                                 return 0;
 295
 296                         d = (unsigned char) (in.s_addr >> 24) & 0xFF;
 297                         c = (unsigned char) (in.s_addr >> 16) & 0xFF;
 298                         b = (unsigned char) (in.s_addr >> 8) & 0xFF;
 299                         a = (unsigned char) in.s_addr & 0xFF;
 300
 301                         snprintf(reversedipbuf, 128, "%d.%d.%d.%d", d, c, b, a);
 302                         reversedip = std::string(reversedipbuf);
 303
 304                         // For each DNSBL, we will run through this lookup
 305                         for (std::vector<DNSBLConfEntry *>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 306                         {
 307                                 // Fill hostname with a dnsbl style host (d.c.b.a.domain.tld)
 308                                 std::string hostname = reversedip + "." + (*i)->domain;
 309
 310                                 /* now we'd need to fire off lookups for `hostname'. */
 311                                 bool cached;
 312                                 DNSBLResolver *r = new DNSBLResolver(this, ServerInstance, hostname, user, user->GetFd(), *i, cached);
 313                                 ServerInstance->AddResolver(r, cached);
 314                         }
 315                 }
 316
 317                 /* don't do anything with this hot potato */
 318                 return 0;
 319         }
 320
 321         virtual int OnStats(char symbol, userrec* user, string_list &results)
 322         {
 323                 if (symbol != 'd')
 324                         return 0;
 325
 326                 unsigned long total_hits = 0, total_misses = 0;
 327
 328                 for (std::vector<DNSBLConfEntry*>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 329                 {
 330                         total_hits += (*i)->stats_hits;
 331                         total_misses += (*i)->stats_misses;
 332
 333                         results.push_back(std::string(ServerInstance->Config->ServerName) + " 304 " + user->nick + " :DNSBLSTATS DNSbl \"" + (*i)->name + "\" had " +
 334                                         ConvToStr((*i)->stats_hits) + " hits and " + ConvToStr((*i)->stats_misses) + " misses");
 335                 }
 336
 337                 results.push_back(std::string(ServerInstance->Config->ServerName) + " 304 " + user->nick + " :DNSBLSTATS Total hits: " + ConvToStr(total_hits));
 338                 results.push_back(std::string(ServerInstance->Config->ServerName) + " 304 " + user->nick + " :DNSBLSTATS Total misses: " + ConvToStr(total_misses));
 339
 340                 return 0;
 341         }
 342 };
 343
 344 // stuff down here is the module-factory stuff.
 345
 346 class ModuleDNSBLFactory : public ModuleFactory
 347 {
 348  public:
 349         ModuleDNSBLFactory()
 350         {
 351         }
 352
 353         ~ModuleDNSBLFactory()
 354         {
 355         }
 356
 357         virtual Module *CreateModule(InspIRCd *Me)
 358         {
 359                 return new ModuleDNSBL(Me);
 360         }
 361
 362 };
 363
 364
 365 extern "C" void * init_module( void )
 366 {
 367         return new ModuleDNSBLFactory;
 368 }