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
  17 #ifndef WINDOWS
  18 #include <sys/types.h>
  19 #include <sys/socket.h>
  20 #include <netinet/in.h>
  21 #include <arpa/inet.h>
  22 #endif
  23
  24 /* $ModDesc: Provides handling of DNS blacklists */
  25
  26 /* Class holding data for a single entry */
  27 class DNSBLConfEntry
  28 {
  29         public:
  30                 enum EnumBanaction { I_UNKNOWN, I_KILL, I_ZLINE, I_KLINE, I_GLINE };
  31                 enum EnumType { A_RECORD, A_BITMASK };
  32                 std::string name, domain, reason;
  33                 EnumBanaction banaction;
  34                 EnumType type;
  35                 long duration;
  36                 int bitmask;
  37                 unsigned char records[256];
  38                 unsigned long stats_hits, stats_misses;
  39                 DNSBLConfEntry(): type(A_BITMASK),duration(86400),bitmask(0),stats_hits(0), stats_misses(0) {}
  40                 ~DNSBLConfEntry() { }
  41 };
  42
  43
  44 /** Resolver for CGI:IRC hostnames encoded in ident/GECOS
  45  */
  46 class DNSBLResolver : public Resolver
  47 {
  48         int theirfd;
  49         User* them;
  50         DNSBLConfEntry *ConfEntry;
  51
  52  public:
  53
  54         DNSBLResolver(Module *me, InspIRCd *ServerInstance, const std::string &hostname, User* u, int userfd, DNSBLConfEntry *conf, bool &cached)
  55                 : Resolver(ServerInstance, hostname, DNS_QUERY_A, cached, me)
  56         {
  57                 theirfd = userfd;
  58                 them = u;
  59                 ConfEntry = conf;
  60         }
  61
  62         /* Note: This may be called multiple times for multiple A record results */
  63         virtual void OnLookupComplete(const std::string &result, unsigned int ttl, bool cached, int resultnum = 0)
  64         {
  65                 /* for bitmask reply types, we arent interested in any but the first result (number 0) */
  66                 if ((ConfEntry->type == DNSBLConfEntry::A_BITMASK) && (resultnum))
  67                         return;
  68
  69                 /* Check the user still exists */
  70                 if ((them) && (them == ServerInstance->SE->GetRef(theirfd)))
  71                 {
  72                         // Now we calculate the bitmask: 256*(256*(256*a+b)+c)+d
  73                         if(result.length())
  74                         {
  75                                 unsigned int bitmask = 0, record = 0;
  76                                 bool show = false, match = false;
  77                                 in_addr resultip;
  78
  79                                 inet_aton(result.c_str(), &resultip);
  80
  81                                 switch (ConfEntry->type)
  82                                 {
  83                                         case DNSBLConfEntry::A_BITMASK:
  84                                                 bitmask = resultip.s_addr >> 24; /* Last octet (network byte order) */
  85                                                 bitmask &= ConfEntry->bitmask;
  86                                                 match = (bitmask != 0);
  87                                         break;
  88                                         case DNSBLConfEntry::A_RECORD:
  89                                                 record = resultip.s_addr >> 24; /* Last octet */
  90                                                 match = (ConfEntry->records[record] == 1);
  91                                         break;
  92                                 }
  93
  94                                 if (match)
  95                                 {
  96                                         std::string reason = ConfEntry->reason;
  97                                         std::string::size_type x = reason.find("%ip%");
  98                                         while (x != std::string::npos)
  99                                         {
 100                                                 reason.erase(x, 4);
 101                                                 reason.insert(x, them->GetIPString());
 102                                                 x = reason.find("%ip%");
 103                                         }
 104
 105                                         ConfEntry->stats_hits++;
 106
 107                                         switch (ConfEntry->banaction)
 108                                         {
 109                                                 case DNSBLConfEntry::I_KILL:
 110                                                 {
 111                                                         User::QuitUser(ServerInstance, them, std::string("Killed (") + reason + ")");
 112                                                         break;
 113                                                 }
 114                                                 case DNSBLConfEntry::I_KLINE:
 115                                                 {
 116                                                         std::string ban = std::string("*@") + them->GetIPString();
 117                                                         if (show)
 118                                                                 ServerInstance->XLines->apply_lines();
 119                                                         show = ServerInstance->XLines->add_kline(ConfEntry->duration, ServerInstance->Config->ServerName, reason.c_str(), ban.c_str());
 120                                                         FOREACH_MOD(I_OnAddKLine,OnAddKLine(ConfEntry->duration, NULL, reason, ban));
 121                                                         break;
 122                                                 }
 123                                                 case DNSBLConfEntry::I_GLINE:
 124                                                 {
 125                                                         std::string ban = std::string("*@") + them->GetIPString();
 126                                                         show = ServerInstance->XLines->add_gline(ConfEntry->duration, ServerInstance->Config->ServerName, reason.c_str(), ban.c_str());
 127                                                         if (show)
 128                                                                 ServerInstance->XLines->apply_lines();
 129                                                         FOREACH_MOD(I_OnAddGLine,OnAddGLine(ConfEntry->duration, NULL, reason, ban));
 130                                                         break;
 131                                                 }
 132                                                 case DNSBLConfEntry::I_ZLINE:
 133                                                 {
 134                                                         show = ServerInstance->XLines->add_zline(ConfEntry->duration, ServerInstance->Config->ServerName, reason.c_str(), them->GetIPString());
 135                                                         if (show)
 136                                                                 ServerInstance->XLines->apply_lines();
 137                                                         FOREACH_MOD(I_OnAddZLine,OnAddZLine(ConfEntry->duration, NULL, reason, them->GetIPString()));
 138                                                         break;
 139                                                 }
 140                                                 case DNSBLConfEntry::I_UNKNOWN:
 141                                                 {
 142                                                         break;
 143                                                 }
 144                                                 break;
 145                                         }
 146
 147                                         if (show)
 148                                         {
 149                                                 ServerInstance->WriteOpers("*** Connecting user %s detected as being on a DNS blacklist (%s) with result %d", them->GetFullRealHost(), ConfEntry->name.c_str(), bitmask);
 150                                         }
 151                                 }
 152                                 else
 153                                         ConfEntry->stats_misses++;
 154                         }
 155                         else
 156                                 ConfEntry->stats_misses++;
 157                 }
 158         }
 159
 160         virtual void OnError(ResolverError e, const std::string &errormessage)
 161         {
 162         }
 163
 164         virtual ~DNSBLResolver()
 165         {
 166         }
 167 };
 168
 169 class ModuleDNSBL : public Module
 170 {
 171  private:
 172         std::vector<DNSBLConfEntry *> DNSBLConfEntries;
 173
 174         /*
 175          *      Convert a string to EnumBanaction
 176          */
 177         DNSBLConfEntry::EnumBanaction str2banaction(const std::string &action)
 178         {
 179                 if(action.compare("KILL")==0)
 180                         return DNSBLConfEntry::I_KILL;
 181                 if(action.compare("KLINE")==0)
 182                         return DNSBLConfEntry::I_KLINE;
 183                 if(action.compare("ZLINE")==0)
 184                         return DNSBLConfEntry::I_ZLINE;
 185                 if(action.compare("GLINE")==0)
 186                         return DNSBLConfEntry::I_GLINE;
 187
 188                 return DNSBLConfEntry::I_UNKNOWN;
 189         }
 190  public:
 191         ModuleDNSBL(InspIRCd *Me) : Module(Me)
 192         {
 193                 ReadConf();
 194         }
 195
 196         virtual ~ModuleDNSBL()
 197         {
 198                 ClearEntries();
 199         }
 200
 201         virtual Version GetVersion()
 202         {
 203                 return Version(2, 0, 0, 1, VF_VENDOR, API_VERSION);
 204         }
 205
 206         void Implements(char* List)
 207         {
 208                 List[I_OnRehash] = List[I_OnUserRegister] = List[I_OnStats] = 1;
 209         }
 210
 211         /** Clear entries and free the mem it was using
 212          */
 213         void ClearEntries()
 214         {
 215                 std::vector<DNSBLConfEntry *>::iterator i;
 216                 for (std::vector<DNSBLConfEntry *>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 217                         delete *i;
 218                 DNSBLConfEntries.clear();
 219         }
 220
 221         /** Fill our conf vector with data
 222          */
 223         virtual void ReadConf()
 224         {
 225                 ConfigReader *MyConf = new ConfigReader(ServerInstance);
 226                 ClearEntries();
 227
 228                 for (int i=0; i< MyConf->Enumerate("dnsbl"); i++)
 229                 {
 230                         DNSBLConfEntry *e = new DNSBLConfEntry();
 231
 232                         e->name = MyConf->ReadValue("dnsbl", "name", i);
 233                         e->reason = MyConf->ReadValue("dnsbl", "reason", i);
 234                         e->domain = MyConf->ReadValue("dnsbl", "domain", i);
 235
 236                         if (MyConf->ReadValue("dnsbl", "type", i) == "bitmask")
 237                         {
 238                                 e->type = DNSBLConfEntry::A_BITMASK;
 239                                 e->bitmask = MyConf->ReadInteger("dnsbl", "bitmask", i, false);
 240                         }
 241                         else
 242                         {
 243                                 memset(e->records, 0, 256);
 244                                 e->type = DNSBLConfEntry::A_RECORD;
 245                                 irc::portparser portrange(MyConf->ReadValue("dnsbl", "records", i), false);
 246                                 long item = -1;
 247                                 while ((item = portrange.GetToken()))
 248                                         e->records[item] = 1;
 249                         }
 250
 251                         e->banaction = str2banaction(MyConf->ReadValue("dnsbl", "action", i));
 252                         e->duration = ServerInstance->Duration(MyConf->ReadValue("dnsbl", "duration", i));
 253
 254                         /* Use portparser for record replies */
 255
 256                         /* yeah, logic here is a little messy */
 257                         if (e->bitmask <= 0)
 258                         {
 259                                 ServerInstance->WriteOpers("*** DNSBL(#%d): invalid bitmask",i);
 260                         }
 261                         else if (e->name.empty())
 262                         {
 263                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid name",i);
 264                         }
 265                         else if (e->domain.empty())
 266                         {
 267                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid domain",i);
 268                         }
 269                         else if (e->banaction == DNSBLConfEntry::I_UNKNOWN)
 270                         {
 271                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid banaction", i);
 272                         }
 273                         else
 274                         {
 275                                 if (e->reason.empty())
 276                                 {
 277                                         ServerInstance->WriteOpers("*** DNSBL(#%d): empty reason, using defaults",i);
 278                                         e->reason = "Your IP has been blacklisted.";
 279                                 }
 280
 281                                 /* add it, all is ok */
 282                                 DNSBLConfEntries.push_back(e);
 283                                 continue;
 284                         }
 285
 286                         /* delete and drop it, error somewhere */
 287                         delete e;
 288                 }
 289
 290                 delete MyConf;
 291         }
 292
 293         virtual void OnRehash(User* user, const std::string &parameter)
 294         {
 295                 ReadConf();
 296         }
 297
 298         virtual int OnUserRegister(User* user)
 299         {
 300                 /* only do lookups on local users */
 301                 if (IS_LOCAL(user))
 302                 {
 303                         /* following code taken from bopm, reverses an IP address. */
 304                         struct in_addr in;
 305                         unsigned char a, b, c, d;
 306                         char reversedipbuf[128];
 307                         std::string reversedip;
 308                         bool success = false;
 309
 310                         if (!inet_aton(user->GetIPString(), &in))
 311                         {
 312 #ifdef IPV6
 313                                 /* We could have an ipv6 address here */
 314                                 std::string x = user->GetIPString();
 315                                 /* Is it a 4in6 address? (Compensate for this kernel kludge that people love) */
 316                                 if (x.find("0::ffff:") == 0)
 317                                 {
 318                                         x.erase(x.begin(), x.begin() + 8);
 319                                         if (inet_aton(x.c_str(), &in))
 320                                                 success = true;
 321                                 }
 322 #endif
 323                         }
 324                         else
 325                         {
 326                                 success = true;
 327                         }
 328
 329                         if (!success)
 330                                 return 0;
 331
 332                         d = (unsigned char) (in.s_addr >> 24) & 0xFF;
 333                         c = (unsigned char) (in.s_addr >> 16) & 0xFF;
 334                         b = (unsigned char) (in.s_addr >> 8) & 0xFF;
 335                         a = (unsigned char) in.s_addr & 0xFF;
 336
 337                         snprintf(reversedipbuf, 128, "%d.%d.%d.%d", d, c, b, a);
 338                         reversedip = std::string(reversedipbuf);
 339
 340                         // For each DNSBL, we will run through this lookup
 341                         for (std::vector<DNSBLConfEntry *>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 342                         {
 343                                 // Fill hostname with a dnsbl style host (d.c.b.a.domain.tld)
 344                                 std::string hostname = reversedip + "." + (*i)->domain;
 345
 346                                 /* now we'd need to fire off lookups for `hostname'. */
 347                                 bool cached;
 348                                 DNSBLResolver *r = new DNSBLResolver(this, ServerInstance, hostname, user, user->GetFd(), *i, cached);
 349                                 ServerInstance->AddResolver(r, cached);
 350                         }
 351                 }
 352
 353                 /* don't do anything with this hot potato */
 354                 return 0;
 355         }
 356
 357         virtual int OnStats(char symbol, User* user, string_list &results)
 358         {
 359                 if (symbol != 'd')
 360                         return 0;
 361
 362                 unsigned long total_hits = 0, total_misses = 0;
 363
 364                 for (std::vector<DNSBLConfEntry*>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 365                 {
 366                         total_hits += (*i)->stats_hits;
 367                         total_misses += (*i)->stats_misses;
 368
 369                         results.push_back(std::string(ServerInstance->Config->ServerName) + " 304 " + user->nick + " :DNSBLSTATS DNSbl \"" + (*i)->name + "\" had " +
 370                                         ConvToStr((*i)->stats_hits) + " hits and " + ConvToStr((*i)->stats_misses) + " misses");
 371                 }
 372
 373                 results.push_back(std::string(ServerInstance->Config->ServerName) + " 304 " + user->nick + " :DNSBLSTATS Total hits: " + ConvToStr(total_hits));
 374                 results.push_back(std::string(ServerInstance->Config->ServerName) + " 304 " + user->nick + " :DNSBLSTATS Total misses: " + ConvToStr(total_misses));
 375
 376                 return 0;
 377         }
 378 };
 379
 380 MODULE_INIT(ModuleDNSBL)