src/modules/m_cloaking.cpp

   1 /*       +------------------------------------+
   2  *       | Inspire Internet Relay Chat Daemon |
   3  *       +------------------------------------+
   4  *
   5  *  InspIRCd: (C) 2002-2008 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 "m_hash.h"
  16
  17 /* $ModDesc: Provides masking of user hostnames */
  18 /* $ModDep: m_hash.h */
  19
  20 /** Handles user mode +x
  21  */
  22 class CloakUser : public ModeHandler
  23 {
  24         std::string prefix;
  25         unsigned int key1;
  26         unsigned int key2;
  27         unsigned int key3;
  28         unsigned int key4;
  29         bool ipalways;
  30         Module* Sender;
  31         Module* HashProvider;
  32         const char *xtab[4];
  33
  34         /** This function takes a domain name string and returns just the last two domain parts,
  35          * or the last domain part if only two are available. Failing that it just returns what it was given.
  36          *
  37          * For example, if it is passed "svn.inspircd.org" it will return ".inspircd.org".
  38          * If it is passed "brainbox.winbot.co.uk" it will return ".co.uk",
  39          * and if it is passed "localhost.localdomain" it will return ".localdomain".
  40          *
  41          * This is used to ensure a significant part of the host is always cloaked (see Bug #216)
  42          */
  43         std::string LastTwoDomainParts(const std::string &host)
  44         {
  45                 int dots = 0;
  46                 std::string::size_type splitdot = host.length();
  47
  48                 for (std::string::size_type x = host.length() - 1; x; --x)
  49                 {
  50                         if (host[x] == '.')
  51                         {
  52                                 splitdot = x;
  53                                 dots++;
  54                         }
  55                         if (dots >= 3)
  56                                 break;
  57                 }
  58
  59                 if (splitdot == host.length())
  60                         return host;
  61                 else
  62                         return host.substr(splitdot);
  63         }
  64
  65  public:
  66         CloakUser(InspIRCd* Instance, Module* Source, Module* Hash) : ModeHandler(Instance, 'x', 0, 0, false, MODETYPE_USER, false), Sender(Source), HashProvider(Hash)
  67         {
  68         }
  69
  70         ModeAction OnModeChange(User* source, User* dest, Channel* channel, std::string &parameter, bool adding)
  71         {
  72                 if (source != dest)
  73                         return MODEACTION_DENY;
  74
  75                 /* For remote clients, we dont take any action, we just allow it.
  76                  * The local server where they are will set their cloak instead.
  77                  */
  78                 if (!IS_LOCAL(dest))
  79                         return MODEACTION_ALLOW;
  80
  81                 /* don't allow this user to spam modechanges */
  82                 dest->IncreasePenalty(5);
  83
  84                 if (adding)
  85                 {
  86                         if(!dest->IsModeSet('x'))
  87                         {
  88                                 /* The mode is being turned on - so attempt to
  89                                  * allocate the user a cloaked host using a non-reversible
  90                                  * algorithm (its simple, but its non-reversible so the
  91                                  * simplicity doesnt really matter). This algorithm
  92                                  * will not work if the user has only one level of domain
  93                                  * naming in their hostname (e.g. if they are on a lan or
  94                                  * are connecting via localhost) -- this doesnt matter much.
  95                                  */
  96
  97                                 char* n1 = strchr(dest->host,'.');
  98                                 char* n2 = strchr(dest->host,':');
  99
 100                                 if (n1 || n2)
 101                                 {
 102                                         unsigned int iv[] = { key1, key2, key3, key4 };
 103                                         std::string a = LastTwoDomainParts(dest->host);
 104                                         std::string b;
 105
 106                                         /* InspIRCd users have two hostnames; A displayed
 107                                          * hostname which can be modified by modules (e.g.
 108                                          * to create vhosts, implement chghost, etc) and a
 109                                          * 'real' hostname which you shouldnt write to.
 110                                          */
 111
 112                                         /* 2008/08/18: add <cloak:ipalways> which always cloaks
 113                                          * the IP, for anonymity. --nenolod
 114                                          */
 115                                         if (!ipalways)
 116                                         {
 117                                                 /** Reset the Hash module, and send it our IV and hex table */
 118                                                 HashResetRequest(Sender, HashProvider).Send();
 119                                                 HashKeyRequest(Sender, HashProvider, iv).Send();
 120                                                 HashHexRequest(Sender, HashProvider, xtab[(*dest->host) % 4]);
 121
 122                                                 /* Generate a cloak using specialized Hash */
 123                                                 std::string hostcloak = prefix + "-" + std::string(HashSumRequest(Sender, HashProvider, dest->host).Send()).substr(0,8) + a;
 124
 125                                                 /* Fix by brain - if the cloaked host is > the max length of a host (64 bytes
 126                                                  * according to the DNS RFC) then tough titty, they get cloaked as an IP.
 127                                                  * Their ISP shouldnt go to town on subdomains, or they shouldnt have a kiddie
 128                                                  * vhost.
 129                                                  */
 130 #ifdef IPV6
 131                                                 in6_addr testaddr;
 132                                                 in_addr testaddr2;
 133                                                 if ((dest->GetProtocolFamily() == AF_INET6) && (inet_pton(AF_INET6,dest->host,&testaddr) < 1) && (hostcloak.length() <= 64))
 134                                                         /* Invalid ipv6 address, and ipv6 user (resolved host) */
 135                                                         b = hostcloak;
 136                                                 else if ((dest->GetProtocolFamily() == AF_INET) && (inet_aton(dest->host,&testaddr2) < 1) && (hostcloak.length() <= 64))
 137                                                         /* Invalid ipv4 address, and ipv4 user (resolved host) */
 138                                                         b = hostcloak;
 139                                                 else
 140                                                         /* Valid ipv6 or ipv4 address (not resolved) ipv4 or ipv6 user */
 141                                                         b = ((!strchr(dest->host,':')) ? Cloak4(dest->host) : Cloak6(dest->host));
 142 #else
 143                                                 in_addr testaddr;
 144                                                 if ((inet_aton(dest->host,&testaddr) < 1) && (hostcloak.length() <= 64))
 145                                                         /* Invalid ipv4 address, and ipv4 user (resolved host) */
 146                                                         b = hostcloak;
 147                                                 else
 148                                                         /* Valid ipv4 address (not resolved) ipv4 user */
 149                                                         b = Cloak4(dest->host);
 150 #endif
 151                                         }
 152                                         else
 153                                         {
 154 #ifdef IPV6
 155                                                 if (dest->GetProtocolFamily() == AF_INET6)
 156                                                         b = Cloak6(dest->GetIPString());
 157 #endif
 158                                                 if (dest->GetProtocolFamily() == AF_INET)
 159                                                         b = Cloak4(dest->GetIPString());
 160                                         }
 161
 162                                         dest->ChangeDisplayedHost(b.c_str());
 163                                 }
 164
 165                                 dest->SetMode('x',true);
 166                                 return MODEACTION_ALLOW;
 167                         }
 168                 }
 169                 else
 170                 {
 171                         if (dest->IsModeSet('x'))
 172                         {
 173                                 /* User is removing the mode, so just restore their real host
 174                                  * and make it match the displayed one.
 175                                  */
 176                                 dest->ChangeDisplayedHost(dest->host);
 177                                 dest->SetMode('x',false);
 178                                 return MODEACTION_ALLOW;
 179                         }
 180                 }
 181
 182                 return MODEACTION_DENY;
 183         }
 184
 185         std::string Cloak4(const char* ip)
 186         {
 187                 unsigned int iv[] = { key1, key2, key3, key4 };
 188                 irc::sepstream seps(ip, '.');
 189                 std::string ra[4];;
 190                 std::string octet[4];
 191                 int i[4];
 192
 193                 for (int j = 0; j < 4; j++)
 194                 {
 195                         seps.GetToken(octet[j]);
 196                         i[j] = atoi(octet[j].c_str());
 197                 }
 198
 199                 octet[3] = octet[0] + "." + octet[1] + "." + octet[2] + "." + octet[3];
 200                 octet[2] = octet[0] + "." + octet[1] + "." + octet[2];
 201                 octet[1] = octet[0] + "." + octet[1];
 202
 203                 /* Reset the Hash module and send it our IV */
 204                 HashResetRequest(Sender, HashProvider).Send();
 205                 HashKeyRequest(Sender, HashProvider, iv).Send();
 206
 207                 /* Send the Hash module a different hex table for each octet group's Hash sum */
 208                 for (int k = 0; k < 4; k++)
 209                 {
 210                         HashHexRequest(Sender, HashProvider, xtab[(iv[k]+i[k]) % 4]).Send();
 211                         ra[k] = std::string(HashSumRequest(Sender, HashProvider, octet[k]).Send()).substr(0,6);
 212                 }
 213                 /* Stick them all together */
 214                 return std::string().append(ra[0]).append(".").append(ra[1]).append(".").append(ra[2]).append(".").append(ra[3]);
 215         }
 216
 217         std::string Cloak6(const char* ip)
 218         {
 219                 /* Theyre using 4in6 (YUCK). Translate as ipv4 cloak */
 220                 if (!strncmp(ip, "0::ffff:", 8))
 221                         return Cloak4(ip + 8);
 222
 223                 /* If we get here, yes it really is an ipv6 ip */
 224                 unsigned int iv[] = { key1, key2, key3, key4 };
 225                 std::vector<std::string> hashies;
 226                 std::string item;
 227                 int rounds = 0;
 228
 229                 /* Reset the Hash module and send it our IV */
 230                 HashResetRequest(Sender, HashProvider).Send();
 231                 HashKeyRequest(Sender, HashProvider, iv).Send();
 232
 233                 for (const char* input = ip; *input; input++)
 234                 {
 235                         item += *input;
 236                         if (item.length() > 7)
 237                         {
 238                                 /* Send the Hash module a different hex table for each octet group's Hash sum */
 239                                 HashHexRequest(Sender, HashProvider, xtab[(key1+rounds) % 4]).Send();
 240                                 hashies.push_back(std::string(HashSumRequest(Sender, HashProvider, item).Send()).substr(0,8));
 241                                 item.clear();
 242                         }
 243                         rounds++;
 244                 }
 245                 if (!item.empty())
 246                 {
 247                         /* Send the Hash module a different hex table for each octet group's Hash sum */
 248                         HashHexRequest(Sender, HashProvider, xtab[(key1+rounds) % 4]).Send();
 249                         hashies.push_back(std::string(HashSumRequest(Sender, HashProvider, item).Send()).substr(0,8));
 250                         item.clear();
 251                 }
 252                 /* Stick them all together */
 253                 return irc::stringjoiner(":", hashies, 0, hashies.size() - 1).GetJoined();
 254         }
 255
 256         void DoRehash()
 257         {
 258                 ConfigReader Conf(ServerInstance);
 259                 bool lowercase;
 260
 261                 /* These are *not* using the need_positive parameter of ReadInteger -
 262                  * that will limit the valid values to only the positive values in a
 263                  * signed int. Instead, accept any value that fits into an int and
 264                  * cast it to an unsigned int. That will, a bit oddly, give us the full
 265                  * spectrum of an unsigned integer. - Special */
 266                 key1 = key2 = key3 = key4 = 0;
 267                 key1 = (unsigned int) Conf.ReadInteger("cloak","key1",0,false);
 268                 key2 = (unsigned int) Conf.ReadInteger("cloak","key2",0,false);
 269                 key3 = (unsigned int) Conf.ReadInteger("cloak","key3",0,false);
 270                 key4 = (unsigned int) Conf.ReadInteger("cloak","key4",0,false);
 271                 prefix = Conf.ReadValue("cloak","prefix",0);
 272                 ipalways = Conf.ReadFlag("cloak", "ipalways", 0);
 273                 lowercase = Conf.ReadFlag("cloak", "lowercase", 0);
 274
 275                 if (!lowercase)
 276                 {
 277                         xtab[0] = "F92E45D871BCA630";
 278                         xtab[1] = "A1B9D80C72E653F4";
 279                         xtab[2] = "1ABC078934DEF562";
 280                         xtab[3] = "ABCDEF5678901234";
 281                 }
 282                 else
 283                 {
 284                         xtab[0] = "f92e45d871bca630";
 285                         xtab[1] = "a1b9d80c72e653f4";
 286                         xtab[2] = "1abc078934def562";
 287                         xtab[3] = "abcdef5678901234";
 288                 }
 289
 290                 if (prefix.empty())
 291                         prefix = ServerInstance->Config->Network;
 292
 293                 if (!key1 || !key2 || !key3 || !key4)
 294                 {
 295                         std::string detail;
 296                         if (!key1)
 297                                 detail = "<cloak:key1> is not valid, it may be set to a too high/low value, or it may not exist.";
 298                         else if (!key2)
 299                                 detail = "<cloak:key2> is not valid, it may be set to a too high/low value, or it may not exist.";
 300                         else if (!key3)
 301                                 detail = "<cloak:key3> is not valid, it may be set to a too high/low value, or it may not exist.";
 302                         else if (!key4)
 303                                 detail = "<cloak:key4> is not valid, it may be set to a too high/low value, or it may not exist.";
 304
 305                         throw ModuleException("You have not defined cloak keys for m_cloaking!!! THIS IS INSECURE AND SHOULD BE CHECKED! - " + detail);
 306                 }
 307         }
 308 };
 309
 310
 311 class ModuleCloaking : public Module
 312 {
 313  private:
 314
 315         CloakUser* cu;
 316         Module* HashModule;
 317
 318  public:
 319         ModuleCloaking(InspIRCd* Me)
 320                 : Module(Me)
 321         {
 322                 /* Attempt to locate the md5 service provider, bail if we can't find it */
 323                 HashModule = ServerInstance->Modules->Find("m_md5.so");
 324                 if (!HashModule)
 325                         throw ModuleException("Can't find m_md5.so. Please load m_md5.so before m_cloaking.so.");
 326
 327                 cu = new CloakUser(ServerInstance, this, HashModule);
 328
 329                 try
 330                 {
 331                         OnRehash(NULL,"");
 332                 }
 333                 catch (CoreException &e)
 334                 {
 335                         delete cu;
 336                         throw e;
 337                 }
 338
 339                 /* Register it with the core */
 340                 if (!ServerInstance->AddMode(cu))
 341                 {
 342                         delete cu;
 343                         throw ModuleException("Could not add new modes!");
 344                 }
 345
 346                 ServerInstance->Modules->UseInterface("HashRequest");
 347
 348                 Implementation eventlist[] = { I_OnRehash };
 349                 ServerInstance->Modules->Attach(eventlist, this, 1);
 350         }
 351
 352         virtual ~ModuleCloaking()
 353         {
 354                 ServerInstance->Modes->DelMode(cu);
 355                 delete cu;
 356                 ServerInstance->Modules->DoneWithInterface("HashRequest");
 357         }
 358
 359         virtual Version GetVersion()
 360         {
 361                 // returns the version number of the module to be
 362                 // listed in /MODULES
 363                 return Version(1,1,0,2,VF_COMMON|VF_VENDOR,API_VERSION);
 364         }
 365
 366         virtual void OnRehash(User* user, const std::string &parameter)
 367         {
 368                 cu->DoRehash();
 369         }
 370
 371 };
 372
 373 MODULE_INIT(ModuleCloaking)