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                 unsigned long stats_hits, stats_misses;
  37                 DNSBLConfEntry(): duration(86400),bitmask(0),stats_hits(0), stats_misses(0) {}
  38                 ~DNSBLConfEntry() { }
  39 };
  40
  41
  42 /** Resolver for CGI:IRC hostnames encoded in ident/GECOS
  43  */
  44 class DNSBLResolver : public Resolver
  45 {
  46         int theirfd;
  47         userrec* them;
  48         DNSBLConfEntry *ConfEntry;
  49
  50     public:
  51         DNSBLResolver(Module *me, InspIRCd *ServerInstance, const std::string &hostname, userrec* u, int userfd, DNSBLConfEntry *conf, bool &cached)
  52                 : Resolver(ServerInstance, hostname, DNS_QUERY_A, cached, me)
  53         {
  54                 theirfd = userfd;
  55                 them = u;
  56                 ConfEntry = conf;
  57         }
  58
  59         virtual void OnLookupComplete(const std::string &result, unsigned int ttl, bool cached)
  60         {
  61                 /* Check the user still exists */
  62                 if ((them) && (them == ServerInstance->SE->GetRef(theirfd)))
  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                                 in_addr resultip;
  69
  70                                 /* Convert the result to an in_addr (we can gaurantee we got ipv4)
  71                                  * Whoever did the loop that was here before, I AM CONFISCATING
  72                                  * YOUR CRACKPIPE. you know who you are. -- Brain
  73                                  */
  74                                 inet_aton(result.c_str(), &resultip);
  75                                 bitmask = resultip.s_addr >> 24; /* Last octet (network byte order */
  76
  77                                 bitmask &= ConfEntry->bitmask;
  78
  79                                 if (bitmask != 0)
  80                                 {
  81                                         std::string reason = ConfEntry->reason;
  82                                         std::string::size_type x = reason.find("%ip%");
  83                                         while (x != std::string::npos)
  84                                         {
  85                                                 reason.erase(x, 4);
  86                                                 reason.insert(x, them->GetIPString());
  87                                                 x = reason.find("%ip%");
  88                                         }
  89
  90                                         ServerInstance->WriteOpers("*** Connecting user %s detected as being on a DNS blacklist (%s) with result %d", them->GetFullRealHost(), ConfEntry->name.c_str(), bitmask);
  91                                         ConfEntry->stats_hits++;
  92
  93                                         switch (ConfEntry->banaction)
  94                                         {
  95                                                 case DNSBLConfEntry::I_KILL:
  96                                                 {
  97                                                         userrec::QuitUser(ServerInstance, them, std::string("Killed (") + reason + ")");
  98                                                         break;
  99                                                 }
 100                                                 case DNSBLConfEntry::I_KLINE:
 101                                                 {
 102                                                         ServerInstance->AddKLine(ConfEntry->duration, ServerInstance->Config->ServerName, reason, std::string("*@") + them->GetIPString());
 103                                                         FOREACH_MOD(I_OnAddKLine,OnAddKLine(ConfEntry->duration, NULL, reason, std::string("*@") + them->GetIPString()));
 104                                                         break;
 105                                                 }
 106                                                 case DNSBLConfEntry::I_GLINE:
 107                                                 {
 108                                                         ServerInstance->AddGLine(ConfEntry->duration, ServerInstance->Config->ServerName, reason, std::string("*@") + them->GetIPString());
 109                                                         FOREACH_MOD(I_OnAddGLine,OnAddGLine(ConfEntry->duration, NULL, 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                                                         FOREACH_MOD(I_OnAddZLine,OnAddZLine(ConfEntry->duration, NULL, reason, them->GetIPString()));
 116                                                         break;
 117                                                 }
 118                                                 case DNSBLConfEntry::I_UNKNOWN:
 119                                                 {
 120                                                         break;
 121                                                 }
 122                                                 break;
 123                                         }
 124                                 }
 125                                 else
 126                                         ConfEntry->stats_misses++;
 127                         }
 128                 }
 129         }
 130
 131         virtual void OnError(ResolverError e, const std::string &errormessage)
 132         {
 133         }
 134
 135         virtual ~DNSBLResolver()
 136         {
 137         }
 138 };
 139
 140 class ModuleDNSBL : public Module
 141 {
 142  private:
 143         std::vector<DNSBLConfEntry *> DNSBLConfEntries;
 144
 145         /*
 146          *      Convert a string to EnumBanaction
 147          */
 148         DNSBLConfEntry::EnumBanaction str2banaction(const std::string &action)
 149         {
 150                 if(action.compare("KILL")==0)
 151                         return DNSBLConfEntry::I_KILL;
 152                 if(action.compare("KLINE")==0)
 153                         return DNSBLConfEntry::I_KLINE;
 154                 if(action.compare("ZLINE")==0)
 155                         return DNSBLConfEntry::I_ZLINE;
 156                 if(action.compare("GLINE")==0)
 157                         return DNSBLConfEntry::I_GLINE;
 158
 159                 return DNSBLConfEntry::I_UNKNOWN;
 160         }
 161  public:
 162         ModuleDNSBL(InspIRCd *Me) : Module::Module(Me)
 163         {
 164                 ReadConf();
 165         }
 166
 167         virtual ~ModuleDNSBL()
 168         {
 169                 ClearEntries();
 170         }
 171
 172         virtual Version GetVersion()
 173         {
 174                 return Version(2, 0, 0, 1, VF_VENDOR, API_VERSION);
 175         }
 176
 177         void Implements(char* List)
 178         {
 179                 List[I_OnRehash] = List[I_OnUserRegister] = List[I_OnStats] = 1;
 180         }
 181
 182         /** Clear entries and free the mem it was using
 183          */
 184         void ClearEntries()
 185         {
 186                 std::vector<DNSBLConfEntry *>::iterator i;
 187                 for (std::vector<DNSBLConfEntry *>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 188                         delete *i;
 189                 DNSBLConfEntries.clear();
 190         }
 191
 192         /** Fill our conf vector with data
 193          */
 194         virtual void ReadConf()
 195         {
 196                 ConfigReader *MyConf = new ConfigReader(ServerInstance);
 197                 ClearEntries();
 198
 199                 for (int i=0; i< MyConf->Enumerate("dnsbl"); i++)
 200                 {
 201                         DNSBLConfEntry *e = new DNSBLConfEntry();
 202
 203                         e->name = MyConf->ReadValue("dnsbl", "name", i);
 204                         e->reason = MyConf->ReadValue("dnsbl", "reason", i);
 205                         e->domain = MyConf->ReadValue("dnsbl", "domain", i);
 206                         e->banaction = str2banaction(MyConf->ReadValue("dnsbl", "action", i));
 207                         e->duration = ServerInstance->Duration(MyConf->ReadValue("dnsbl", "duration", i).c_str());
 208                         e->bitmask = MyConf->ReadInteger("dnsbl", "bitmask", i, false);
 209
 210                         /* yeah, logic here is a little messy */
 211                         if (e->bitmask <= 0)
 212                         {
 213                                 ServerInstance->WriteOpers("*** DNSBL(#%d): invalid bitmask",i);
 214                         }
 215                         else if (e->name == "")
 216                         {
 217                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid name",i);
 218                         }
 219                         else if (e->domain == "")
 220                         {
 221                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid domain",i);
 222                         }
 223                         else if (e->banaction == DNSBLConfEntry::I_UNKNOWN)
 224                         {
 225                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid banaction", i);
 226                         }
 227                         else
 228                         {
 229                                 if (e->reason == "")
 230                                 {
 231                                         ServerInstance->WriteOpers("*** DNSBL(#%d): empty reason, using defaults",i);
 232                                         e->reason = "Your IP has been blacklisted.";
 233                                 }
 234
 235                                 /* add it, all is ok */
 236                                 DNSBLConfEntries.push_back(e);
 237                                 continue;
 238                         }
 239
 240                         /* delete and drop it, error somewhere */
 241                         delete e;
 242                 }
 243
 244                 delete MyConf;
 245         }
 246
 247         virtual void OnRehash(userrec* user, 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                         bool success = false;
 265
 266                         if (!inet_aton(user->GetIPString(), &in))
 267                         {
 268 #ifdef IPV6
 269                                 /* We could have an ipv6 address here */
 270                                 std::string x = user->GetIPString();
 271                                 /* Is it a 4in6 address? (Compensate for this kernel kludge that people love) */
 272                                 if (x.find("0::ffff:") == 0)
 273                                 {
 274                                         x.erase(x.begin(), x.begin() + 8);
 275                                         if (inet_aton(x.c_str(), &in))
 276                                                 success = true;
 277                                 }
 278 #endif
 279                         }
 280                         else
 281                         {
 282                                 success = true;
 283                         }
 284
 285                         if (!success)
 286                                 return 0;
 287
 288                         d = (unsigned char) (in.s_addr >> 24) & 0xFF;
 289                         c = (unsigned char) (in.s_addr >> 16) & 0xFF;
 290                         b = (unsigned char) (in.s_addr >> 8) & 0xFF;
 291                         a = (unsigned char) in.s_addr & 0xFF;
 292
 293                         snprintf(reversedipbuf, 128, "%d.%d.%d.%d", d, c, b, a);
 294                         reversedip = std::string(reversedipbuf);
 295
 296                         // For each DNSBL, we will run through this lookup
 297                         for (std::vector<DNSBLConfEntry *>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 298                         {
 299                                 // Fill hostname with a dnsbl style host (d.c.b.a.domain.tld)
 300                                 std::string hostname = reversedip + "." + (*i)->domain;
 301
 302                                 /* now we'd need to fire off lookups for `hostname'. */
 303                                 bool cached;
 304                                 DNSBLResolver *r = new DNSBLResolver(this, ServerInstance, hostname, user, user->GetFd(), *i, cached);
 305                                 ServerInstance->AddResolver(r, cached);
 306                         }
 307                 }
 308
 309                 /* don't do anything with this hot potato */
 310                 return 0;
 311         }
 312
 313         virtual int OnStats(char symbol, userrec* user, string_list &results)
 314         {
 315                 if (symbol != 'd')
 316                         return 0;
 317
 318                 unsigned long total_hits = 0, total_misses = 0;
 319
 320                 for (std::vector<DNSBLConfEntry*>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 321                 {
 322                         total_hits += (*i)->stats_hits;
 323                         total_misses += (*i)->stats_misses;
 324
 325                         results.push_back(std::string(ServerInstance->Config->ServerName) + " 304 " + user->nick + " :DNSBLSTATS DNSbl \"" + (*i)->name + "\" had " +
 326                                         ConvToStr((*i)->stats_hits) + " hits and " + ConvToStr((*i)->stats_misses) + " misses");
 327                 }
 328
 329                 results.push_back(std::string(ServerInstance->Config->ServerName) + " 304 " + user->nick + " :DNSBLSTATS Total hits: " + ConvToStr(total_hits));
 330                 results.push_back(std::string(ServerInstance->Config->ServerName) + " 304 " + user->nick + " :DNSBLSTATS Total misses: " + ConvToStr(total_misses));
 331
 332                 return 0;
 333         }
 334 };
 335
 336 // stuff down here is the module-factory stuff.
 337
 338 class ModuleDNSBLFactory : public ModuleFactory
 339 {
 340  public:
 341         ModuleDNSBLFactory()
 342         {
 343         }
 344
 345         ~ModuleDNSBLFactory()
 346         {
 347         }
 348
 349         virtual Module *CreateModule(InspIRCd *Me)
 350         {
 351                 return new ModuleDNSBL(Me);
 352         }
 353
 354 };
 355
 356
 357 extern "C" void * init_module( void )
 358 {
 359         return new ModuleDNSBLFactory;
 360 }