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 #endif
  27
  28 /* $ModDesc: Provides handling of DNS blacklists */
  29
  30 /* Class holding data for a single entry */
  31 class DNSBLConfEntry
  32 {
  33         public:
  34                 enum EnumBanaction { I_UNKNOWN, I_KILL, I_ZLINE, I_KLINE, I_GLINE };
  35                 enum EnumType { A_RECORD, A_BITMASK };
  36                 std::string name, domain, reason;
  37                 EnumBanaction banaction;
  38                 EnumType type;
  39                 long duration;
  40                 int bitmask;
  41                 unsigned char records[256];
  42                 unsigned long stats_hits, stats_misses;
  43                 DNSBLConfEntry(): type(A_BITMASK),duration(86400),bitmask(0),stats_hits(0), stats_misses(0) {}
  44                 ~DNSBLConfEntry() { }
  45 };
  46
  47
  48 /** Resolver for CGI:IRC hostnames encoded in ident/GECOS
  49  */
  50 class DNSBLResolver : public Resolver
  51 {
  52         int theirfd;
  53         userrec* them;
  54         DNSBLConfEntry *ConfEntry;
  55
  56  public:
  57
  58         DNSBLResolver(Module *me, InspIRCd *ServerInstance, const std::string &hostname, userrec* u, int userfd, DNSBLConfEntry *conf, bool &cached)
  59                 : Resolver(ServerInstance, hostname, DNS_QUERY_A, cached, me)
  60         {
  61                 theirfd = userfd;
  62                 them = u;
  63                 ConfEntry = conf;
  64         }
  65
  66         /* Note: This may be called multiple times for multiple A record results */
  67         virtual void OnLookupComplete(const std::string &result, unsigned int ttl, bool cached, int resultnum = 0)
  68         {
  69                 /* for bitmask reply types, we arent interested in any but the first result (number 0) */
  70                 if ((ConfEntry->type == DNSBLConfEntry::A_BITMASK) && (resultnum))
  71                         return;
  72
  73                 /* Check the user still exists */
  74                 if ((them) && (them == ServerInstance->SE->GetRef(theirfd)))
  75                 {
  76                         // Now we calculate the bitmask: 256*(256*(256*a+b)+c)+d
  77                         if(result.length())
  78                         {
  79                                 unsigned int bitmask = 0, record = 0;
  80                                 bool show = false, match = false;
  81                                 in_addr resultip;
  82
  83                                 inet_aton(result.c_str(), &resultip);
  84
  85                                 switch (ConfEntry->type)
  86                                 {
  87                                         case DNSBLConfEntry::A_BITMASK:
  88                                                 bitmask = resultip.s_addr >> 24; /* Last octet (network byte order) */
  89                                                 bitmask &= ConfEntry->bitmask;
  90                                                 match = (bitmask != 0);
  91                                         break;
  92                                         case DNSBLConfEntry::A_RECORD:
  93                                                 record = resultip.s_addr >> 24; /* Last octet */
  94                                                 match = (ConfEntry->records[record] == 1);
  95                                         break;
  96                                 }
  97
  98                                 if (match)
  99                                 {
 100                                         std::string reason = ConfEntry->reason;
 101                                         std::string::size_type x = reason.find("%ip%");
 102                                         while (x != std::string::npos)
 103                                         {
 104                                                 reason.erase(x, 4);
 105                                                 reason.insert(x, them->GetIPString());
 106                                                 x = reason.find("%ip%");
 107                                         }
 108
 109                                         ConfEntry->stats_hits++;
 110
 111                                         switch (ConfEntry->banaction)
 112                                         {
 113                                                 case DNSBLConfEntry::I_KILL:
 114                                                 {
 115                                                         userrec::QuitUser(ServerInstance, them, std::string("Killed (") + reason + ")");
 116                                                         break;
 117                                                 }
 118                                                 case DNSBLConfEntry::I_KLINE:
 119                                                 {
 120                                                         std::string ban = std::string("*@") + them->GetIPString();
 121                                                         if (show)
 122                                                                 ServerInstance->XLines->apply_lines(APPLY_KLINES);
 123                                                         show = ServerInstance->XLines->add_kline(ConfEntry->duration, ServerInstance->Config->ServerName, reason.c_str(), ban.c_str());
 124                                                         FOREACH_MOD(I_OnAddKLine,OnAddKLine(ConfEntry->duration, NULL, reason, ban));
 125                                                         break;
 126                                                 }
 127                                                 case DNSBLConfEntry::I_GLINE:
 128                                                 {
 129                                                         std::string ban = std::string("*@") + them->GetIPString();
 130                                                         show = ServerInstance->XLines->add_gline(ConfEntry->duration, ServerInstance->Config->ServerName, reason.c_str(), ban.c_str());
 131                                                         if (show)
 132                                                                 ServerInstance->XLines->apply_lines(APPLY_GLINES);
 133                                                         FOREACH_MOD(I_OnAddGLine,OnAddGLine(ConfEntry->duration, NULL, reason, ban));
 134                                                         break;
 135                                                 }
 136                                                 case DNSBLConfEntry::I_ZLINE:
 137                                                 {
 138                                                         show = ServerInstance->XLines->add_zline(ConfEntry->duration, ServerInstance->Config->ServerName, reason.c_str(), them->GetIPString());
 139                                                         if (show)
 140                                                                 ServerInstance->XLines->apply_lines(APPLY_ZLINES);
 141                                                         FOREACH_MOD(I_OnAddZLine,OnAddZLine(ConfEntry->duration, NULL, reason, them->GetIPString()));
 142                                                         break;
 143                                                 }
 144                                                 case DNSBLConfEntry::I_UNKNOWN:
 145                                                 {
 146                                                         break;
 147                                                 }
 148                                                 break;
 149                                         }
 150
 151                                         if (show)
 152                                         {
 153                                                 ServerInstance->WriteOpers("*** Connecting user %s detected as being on a DNS blacklist (%s) with result %d", them->GetFullRealHost(), ConfEntry->name.c_str(), bitmask);
 154                                         }
 155                                 }
 156                                 else
 157                                         ConfEntry->stats_misses++;
 158                         }
 159                         else
 160                                 ConfEntry->stats_misses++;
 161                 }
 162         }
 163
 164         virtual void OnError(ResolverError e, const std::string &errormessage)
 165         {
 166         }
 167
 168         virtual ~DNSBLResolver()
 169         {
 170         }
 171 };
 172
 173 class ModuleDNSBL : public Module
 174 {
 175  private:
 176         std::vector<DNSBLConfEntry *> DNSBLConfEntries;
 177
 178         /*
 179          *      Convert a string to EnumBanaction
 180          */
 181         DNSBLConfEntry::EnumBanaction str2banaction(const std::string &action)
 182         {
 183                 if(action.compare("KILL")==0)
 184                         return DNSBLConfEntry::I_KILL;
 185                 if(action.compare("KLINE")==0)
 186                         return DNSBLConfEntry::I_KLINE;
 187                 if(action.compare("ZLINE")==0)
 188                         return DNSBLConfEntry::I_ZLINE;
 189                 if(action.compare("GLINE")==0)
 190                         return DNSBLConfEntry::I_GLINE;
 191
 192                 return DNSBLConfEntry::I_UNKNOWN;
 193         }
 194  public:
 195         ModuleDNSBL(InspIRCd *Me) : Module(Me)
 196         {
 197                 ReadConf();
 198         }
 199
 200         virtual ~ModuleDNSBL()
 201         {
 202                 ClearEntries();
 203         }
 204
 205         virtual Version GetVersion()
 206         {
 207                 return Version(2, 0, 0, 1, VF_VENDOR, API_VERSION);
 208         }
 209
 210         void Implements(char* List)
 211         {
 212                 List[I_OnRehash] = List[I_OnUserRegister] = List[I_OnStats] = 1;
 213         }
 214
 215         /** Clear entries and free the mem it was using
 216          */
 217         void ClearEntries()
 218         {
 219                 std::vector<DNSBLConfEntry *>::iterator i;
 220                 for (std::vector<DNSBLConfEntry *>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 221                         delete *i;
 222                 DNSBLConfEntries.clear();
 223         }
 224
 225         /** Fill our conf vector with data
 226          */
 227         virtual void ReadConf()
 228         {
 229                 ConfigReader *MyConf = new ConfigReader(ServerInstance);
 230                 ClearEntries();
 231
 232                 for (int i=0; i< MyConf->Enumerate("dnsbl"); i++)
 233                 {
 234                         DNSBLConfEntry *e = new DNSBLConfEntry();
 235
 236                         e->name = MyConf->ReadValue("dnsbl", "name", i);
 237                         e->reason = MyConf->ReadValue("dnsbl", "reason", i);
 238                         e->domain = MyConf->ReadValue("dnsbl", "domain", i);
 239
 240                         if (MyConf->ReadValue("dnsbl", "type", i) == "bitmask")
 241                         {
 242                                 e->type = DNSBLConfEntry::A_BITMASK;
 243                                 e->bitmask = MyConf->ReadInteger("dnsbl", "bitmask", i, false);
 244                         }
 245                         else
 246                         {
 247                                 memset(e->records, 0, 256);
 248                                 e->type = DNSBLConfEntry::A_RECORD;
 249                                 irc::portparser portrange(MyConf->ReadValue("dnsbl", "records", i), false);
 250                                 long item = -1;
 251                                 while ((item = portrange.GetToken()))
 252                                         e->records[item] = 1;
 253                         }
 254
 255                         e->banaction = str2banaction(MyConf->ReadValue("dnsbl", "action", i));
 256                         e->duration = ServerInstance->Duration(MyConf->ReadValue("dnsbl", "duration", i));
 257
 258                         /* Use portparser for record replies */
 259
 260                         /* yeah, logic here is a little messy */
 261                         if (e->bitmask <= 0)
 262                         {
 263                                 ServerInstance->WriteOpers("*** DNSBL(#%d): invalid bitmask",i);
 264                         }
 265                         else if (e->name.empty())
 266                         {
 267                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid name",i);
 268                         }
 269                         else if (e->domain.empty())
 270                         {
 271                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid domain",i);
 272                         }
 273                         else if (e->banaction == DNSBLConfEntry::I_UNKNOWN)
 274                         {
 275                                 ServerInstance->WriteOpers("*** DNSBL(#%d): Invalid banaction", i);
 276                         }
 277                         else
 278                         {
 279                                 if (e->reason.empty())
 280                                 {
 281                                         ServerInstance->WriteOpers("*** DNSBL(#%d): empty reason, using defaults",i);
 282                                         e->reason = "Your IP has been blacklisted.";
 283                                 }
 284
 285                                 /* add it, all is ok */
 286                                 DNSBLConfEntries.push_back(e);
 287                                 continue;
 288                         }
 289
 290                         /* delete and drop it, error somewhere */
 291                         delete e;
 292                 }
 293
 294                 delete MyConf;
 295         }
 296
 297         virtual void OnRehash(userrec* user, const std::string &parameter)
 298         {
 299                 ReadConf();
 300         }
 301
 302         virtual int OnUserRegister(userrec* user)
 303         {
 304                 /* only do lookups on local users */
 305                 if (IS_LOCAL(user))
 306                 {
 307                         /* following code taken from bopm, reverses an IP address. */
 308                         struct in_addr in;
 309                         unsigned char a, b, c, d;
 310                         char reversedipbuf[128];
 311                         std::string reversedip;
 312                         bool success = false;
 313
 314                         if (!inet_aton(user->GetIPString(), &in))
 315                         {
 316 #ifdef IPV6
 317                                 /* We could have an ipv6 address here */
 318                                 std::string x = user->GetIPString();
 319                                 /* Is it a 4in6 address? (Compensate for this kernel kludge that people love) */
 320                                 if (x.find("0::ffff:") == 0)
 321                                 {
 322                                         x.erase(x.begin(), x.begin() + 8);
 323                                         if (inet_aton(x.c_str(), &in))
 324                                                 success = true;
 325                                 }
 326 #endif
 327                         }
 328                         else
 329                         {
 330                                 success = true;
 331                         }
 332
 333                         if (!success)
 334                                 return 0;
 335
 336                         d = (unsigned char) (in.s_addr >> 24) & 0xFF;
 337                         c = (unsigned char) (in.s_addr >> 16) & 0xFF;
 338                         b = (unsigned char) (in.s_addr >> 8) & 0xFF;
 339                         a = (unsigned char) in.s_addr & 0xFF;
 340
 341                         snprintf(reversedipbuf, 128, "%d.%d.%d.%d", d, c, b, a);
 342                         reversedip = std::string(reversedipbuf);
 343
 344                         // For each DNSBL, we will run through this lookup
 345                         for (std::vector<DNSBLConfEntry *>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 346                         {
 347                                 // Fill hostname with a dnsbl style host (d.c.b.a.domain.tld)
 348                                 std::string hostname = reversedip + "." + (*i)->domain;
 349
 350                                 /* now we'd need to fire off lookups for `hostname'. */
 351                                 bool cached;
 352                                 DNSBLResolver *r = new DNSBLResolver(this, ServerInstance, hostname, user, user->GetFd(), *i, cached);
 353                                 ServerInstance->AddResolver(r, cached);
 354                         }
 355                 }
 356
 357                 /* don't do anything with this hot potato */
 358                 return 0;
 359         }
 360
 361         virtual int OnStats(char symbol, userrec* user, string_list &results)
 362         {
 363                 if (symbol != 'd')
 364                         return 0;
 365
 366                 unsigned long total_hits = 0, total_misses = 0;
 367
 368                 for (std::vector<DNSBLConfEntry*>::iterator i = DNSBLConfEntries.begin(); i != DNSBLConfEntries.end(); i++)
 369                 {
 370                         total_hits += (*i)->stats_hits;
 371                         total_misses += (*i)->stats_misses;
 372
 373                         results.push_back(std::string(ServerInstance->Config->ServerName) + " 304 " + user->nick + " :DNSBLSTATS DNSbl \"" + (*i)->name + "\" had " +
 374                                         ConvToStr((*i)->stats_hits) + " hits and " + ConvToStr((*i)->stats_misses) + " misses");
 375                 }
 376
 377                 results.push_back(std::string(ServerInstance->Config->ServerName) + " 304 " + user->nick + " :DNSBLSTATS Total hits: " + ConvToStr(total_hits));
 378                 results.push_back(std::string(ServerInstance->Config->ServerName) + " 304 " + user->nick + " :DNSBLSTATS Total misses: " + ConvToStr(total_misses));
 379
 380                 return 0;
 381         }
 382 };
 383
 384 MODULE_INIT(ModuleDNSBL)