/* +------------------------------------+ * | Inspire Internet Relay Chat Daemon | * +------------------------------------+ * * InspIRCd: (C) 2002-2009 InspIRCd Development Team * See: http://wiki.inspircd.org/Credits * * This program is free but copyrighted software; see * the file COPYING for details. * * --------------------------------------------------- */ #include "inspircd.h" #include "m_hash.h" /* $ModDesc: Provides masking of user hostnames */ enum CloakMode { /** 1.2-compatible host-based cloak */ MODE_COMPAT_HOST, /** 1.2-compatible IP-only cloak */ MODE_COMPAT_IPONLY, /** 2.0 cloak of "half" of the hostname plus the full IP hash */ MODE_HALF_CLOAK, /** 2.0 cloak of IP hash, split at 2 common CIDR range points */ MODE_OPAQUE }; // lowercase-only encoding similar to base64, used for hash output static const char base32[] = "0123456789abcdefghijklmnopqrstuv"; /** Handles user mode +x */ class CloakUser : public ModeHandler { public: LocalStringExt ext; CloakUser(Module* source) : ModeHandler(source, "cloak", 'x', PARAM_NONE, MODETYPE_USER), ext("cloaked_host", source) { } ModeAction OnModeChange(User* source, User* dest, Channel* channel, std::string ¶meter, bool adding) { /* For remote clients, we don't take any action, we just allow it. * The local server where they are will set their cloak instead. * This is fine, as we will receive it later. */ if (!IS_LOCAL(dest)) { dest->SetMode('x',adding); return MODEACTION_ALLOW; } /* don't allow this user to spam modechanges */ dest->IncreasePenalty(5); if (adding) { if(!dest->IsModeSet('x')) { /* The mode is being turned on - so attempt to * allocate the user a cloaked host using a non-reversible * algorithm (its simple, but its non-reversible so the * simplicity doesnt really matter). This algorithm * will not work if the user has only one level of domain * naming in their hostname (e.g. if they are on a lan or * are connecting via localhost) -- this doesnt matter much. */ std::string* cloak = ext.get(dest); if (!cloak) { /* Force creation of missing cloak */ creator->OnUserConnect(dest); cloak = ext.get(dest); } if (cloak) { dest->ChangeDisplayedHost(cloak->c_str()); dest->SetMode('x',true); return MODEACTION_ALLOW; } } } else { if (dest->IsModeSet('x')) { /* User is removing the mode, so just restore their real host * and make it match the displayed one. */ dest->ChangeDisplayedHost(dest->host.c_str()); dest->SetMode('x',false); return MODEACTION_ALLOW; } } return MODEACTION_DENY; } }; class ModuleCloaking : public Module { private: CloakUser cu; CloakMode mode; std::string prefix; std::string key; unsigned int compatkey[4]; const char* xtab[4]; Module* HashProvider; public: ModuleCloaking() : cu(this) { /* Attempt to locate the md5 service provider, bail if we can't find it */ HashProvider = ServerInstance->Modules->Find("m_md5.so"); if (!HashProvider) throw ModuleException("Can't find m_md5.so. Please load m_md5.so before m_cloaking.so."); OnRehash(NULL); /* Register it with the core */ if (!ServerInstance->Modes->AddMode(&cu)) throw ModuleException("Could not add new modes!"); ServerInstance->Modules->UseInterface("HashRequest"); ServerInstance->Extensions.Register(&cu.ext); Implementation eventlist[] = { I_OnRehash, I_OnCheckBan, I_OnUserConnect }; ServerInstance->Modules->Attach(eventlist, this, 3); CloakExistingUsers(); } /** This function takes a domain name string and returns just the last two domain parts, * or the last domain part if only two are available. Failing that it just returns what it was given. * * For example, if it is passed "svn.inspircd.org" it will return ".inspircd.org". * If it is passed "brainbox.winbot.co.uk" it will return ".co.uk", * and if it is passed "localhost.localdomain" it will return ".localdomain". * * This is used to ensure a significant part of the host is always cloaked (see Bug #216) */ std::string LastTwoDomainParts(const std::string &host) { int dots = 0; std::string::size_type splitdot = host.length(); for (std::string::size_type x = host.length() - 1; x; --x) { if (host[x] == '.') { splitdot = x; dots++; } if (dots >= 3) break; } if (splitdot == host.length()) return host; else return host.substr(splitdot); } std::string CompatCloak4(const char* ip) { irc::sepstream seps(ip, '.'); std::string octet[4]; int i[4]; for (int j = 0; j < 4; j++) { seps.GetToken(octet[j]); i[j] = atoi(octet[j].c_str()); } octet[3] = octet[0] + "." + octet[1] + "." + octet[2] + "." + octet[3]; octet[2] = octet[0] + "." + octet[1] + "." + octet[2]; octet[1] = octet[0] + "." + octet[1]; /* Reset the Hash module and send it our IV */ std::string rv; /* Send the Hash module a different hex table for each octet group's Hash sum */ for (int k = 0; k < 4; k++) { HashRequestIV hash(this, HashProvider, compatkey, xtab[(compatkey[k]+i[k]) % 4], octet[k]); rv.append(hash.result.substr(0,6)); if (k < 3) rv.append("."); } /* Stick them all together */ return rv; } std::string CompatCloak6(const char* ip) { std::vector hashies; std::string item; int rounds = 0; /* Reset the Hash module and send it our IV */ for (const char* input = ip; *input; input++) { item += *input; if (item.length() > 7) { HashRequestIV hash(this, HashProvider, compatkey, xtab[(compatkey[1]+rounds) % 4], item); hashies.push_back(hash.result.substr(0,8)); item.clear(); } rounds++; } if (!item.empty()) { HashRequestIV hash(this, HashProvider, compatkey, xtab[(compatkey[1]+rounds) % 4], item); hashies.push_back(hash.result.substr(0,8)); } /* Stick them all together */ return irc::stringjoiner(":", hashies, 0, hashies.size() - 1).GetJoined(); } std::string ReversePartialIP(const irc::sockets::sockaddrs& ip) { char rv[50]; if (ip.sa.sa_family == AF_INET6) { snprintf(rv, 50, ".%02x%02x.%02x%02x.%02x%02x.IP", ip.in6.sin6_addr.s6_addr[4], ip.in6.sin6_addr.s6_addr[5], ip.in6.sin6_addr.s6_addr[2], ip.in6.sin6_addr.s6_addr[3], ip.in6.sin6_addr.s6_addr[0], ip.in6.sin6_addr.s6_addr[1]); } else { const unsigned char* ip4 = (const unsigned char*)&ip.in4.sin_addr; snprintf(rv, 50, ".%d.%d.IP", ip4[1], ip4[0]); } return rv; } std::string SegmentIP(const irc::sockets::sockaddrs& ip) { std::string bindata; int hop1, hop2; if (ip.sa.sa_family == AF_INET6) { bindata = std::string((const char*)ip.in6.sin6_addr.s6_addr, 16); hop1 = 8; hop2 = 6; } else { bindata = std::string((const char*)&ip.in4.sin_addr, 4); hop1 = 3; hop2 = 2; } std::string rv; rv.reserve(prefix.length() + 30); rv.append(prefix); rv.append(SegmentCloak(bindata, 2)); rv.append(1, '.'); bindata.erase(hop1); rv.append(SegmentCloak(bindata, 3)); rv.append(1, '.'); bindata.erase(hop2); rv.append(SegmentCloak(bindata, 4)); rv.append(".IP"); return rv; } std::string SegmentCloak(const std::string& item, char id) { std::string input; input.reserve(key.length() + 3 + item.length()); input.append(1, id); input.append(key); input.append(1, 0); // null does not terminate a C++ string input.append(item); HashRequest hash(this, HashProvider, input); std::string rv = hash.binresult.substr(0,6); for(int i=0; i < 6; i++) { // this discards 3 bits per byte. We have an // overabundance of bits in the hash output, doesn't // matter which ones we are discarding. rv[i] = base32[rv[i] & 0x1F]; } return rv; } void CloakExistingUsers() { std::string* cloak; for (std::vector::iterator u = ServerInstance->Users->local_users.begin(); u != ServerInstance->Users->local_users.end(); u++) { cloak = cu.ext.get(*u); if (!cloak) { OnUserConnect(*u); } } } ModResult OnCheckBan(User* user, Channel* chan, const std::string& mask) { char cmask[MAXBUF]; std::string* cloak = cu.ext.get(user); /* Check if they have a cloaked host, but are not using it */ if (cloak && *cloak != user->dhost) { snprintf(cmask, MAXBUF, "%s!%s@%s", user->nick.c_str(), user->ident.c_str(), cloak->c_str()); if (InspIRCd::Match(cmask,mask)) return MOD_RES_DENY; } return MOD_RES_PASSTHRU; } void Prioritize() { /* Needs to be after m_banexception etc. */ ServerInstance->Modules->SetPriority(this, I_OnCheckBan, PRIORITY_LAST); } ~ModuleCloaking() { ServerInstance->Modules->DoneWithInterface("HashRequest"); } Version GetVersion() { // returns the version number of the module to be // listed in /MODULES return Version("Provides masking of user hostnames", VF_COMMON|VF_VENDOR); } void OnRehash(User* user) { ConfigReader Conf; prefix = Conf.ReadValue("cloak","prefix",0); std::string modestr = Conf.ReadValue("cloak", "mode", 0); if (modestr == "compat-host") mode = MODE_COMPAT_HOST; else if (modestr == "compat-ip") mode = MODE_COMPAT_IPONLY; else if (modestr == "half") mode = MODE_HALF_CLOAK; else if (modestr == "full") mode = MODE_OPAQUE; else throw ModuleException("Bad value for ; must be one of compat-host, compat-ip, half, full"); if (mode == MODE_COMPAT_HOST || mode == MODE_COMPAT_IPONLY) { bool lowercase = Conf.ReadFlag("cloak", "lowercase", 0); /* These are *not* using the need_positive parameter of ReadInteger - * that will limit the valid values to only the positive values in a * signed int. Instead, accept any value that fits into an int and * cast it to an unsigned int. That will, a bit oddly, give us the full * spectrum of an unsigned integer. - Special * * We must limit the keys or else we get different results on * amd64/x86 boxes. - psychon */ const unsigned int limit = 0x80000000; compatkey[1] = (unsigned int) Conf.ReadInteger("cloak","key1",0,false); compatkey[2] = (unsigned int) Conf.ReadInteger("cloak","key2",0,false); compatkey[3] = (unsigned int) Conf.ReadInteger("cloak","key3",0,false); compatkey[4] = (unsigned int) Conf.ReadInteger("cloak","key4",0,false); if (!lowercase) { xtab[0] = "F92E45D871BCA630"; xtab[1] = "A1B9D80C72E653F4"; xtab[2] = "1ABC078934DEF562"; xtab[3] = "ABCDEF5678901234"; } else { xtab[0] = "f92e45d871bca630"; xtab[1] = "a1b9d80c72e653f4"; xtab[2] = "1abc078934def562"; xtab[3] = "abcdef5678901234"; } if (prefix.empty()) prefix = ServerInstance->Config->Network; if (!compatkey[1] || !compatkey[2] || !compatkey[3] || !compatkey[4] || compatkey[1] >= limit || compatkey[2] >= limit || compatkey[3] >= limit || compatkey[4] >= limit) { std::string detail; if (!compatkey[1] || compatkey[1] >= limit) detail = " is not valid, it may be set to a too high/low value, or it may not exist."; else if (!compatkey[2] || compatkey[2] >= limit) detail = " is not valid, it may be set to a too high/low value, or it may not exist."; else if (!compatkey[3] || compatkey[3] >= limit) detail = " is not valid, it may be set to a too high/low value, or it may not exist."; else if (!compatkey[4] || compatkey[4] >= limit) detail = " is not valid, it may be set to a too high/low value, or it may not exist."; throw ModuleException("You have not defined cloak keys for m_cloaking!!! THIS IS INSECURE AND SHOULD BE CHECKED! - " + detail); } } else { key = Conf.ReadFlag("cloak", "key", 0); if (key.empty() || key == "secret") throw ModuleException("You have not defined cloak keys for m_cloaking. Define as a network-wide secret."); } } void OnUserConnect(User* dest) { std::string* cloak = cu.ext.get(dest); if (cloak) return; if (dest->host.find('.') == std::string::npos && dest->host.find(':') == std::string::npos) return; std::string ipstr = dest->GetIPString(); std::string chost; switch (mode) { case MODE_COMPAT_HOST: { if (ipstr != dest->host) { std::string tail = LastTwoDomainParts(dest->host); /** Reset the Hash module, and send it our IV and hex table */ HashRequestIV hash(this, HashProvider, compatkey, xtab[(dest->host[0]) % 4], dest->host); /* Generate a cloak using specialized Hash */ chost = prefix + "-" + hash.result.substr(0,8) + tail; /* Fix by brain - if the cloaked host is > the max length of a host (64 bytes * according to the DNS RFC) then they get cloaked as an IP. */ if (chost.length() <= 64) break; } // fall through to IP cloak } case MODE_COMPAT_IPONLY: if (dest->client_sa.sa.sa_family == AF_INET6) chost = CompatCloak6(ipstr.c_str()); else chost = CompatCloak4(ipstr.c_str()); break; case MODE_HALF_CLOAK: { std::string tail; if (ipstr != dest->host) tail = LastTwoDomainParts(dest->host); if (tail.empty() || tail.length() > 50) tail = ReversePartialIP(dest->client_sa); chost = prefix + SegmentCloak(dest->host, 1) + tail; break; } case MODE_OPAQUE: default: chost = prefix + SegmentIP(dest->client_sa); } cu.ext.set(dest,chost); } }; MODULE_INIT(ModuleCloaking)