X-Git-Url: https://git.netwichtig.de/gitweb/?a=blobdiff_plain;f=src%2Fcoremods%2Fcore_dns.cpp;h=dbfb0b5828efa4d0b4cacdeb3edf970c4d38ac0a;hb=a601cf2f0d9754e4bb11a28ce8954a86ad4e367e;hp=1e7f6afca9325fb66681299966db5fe1057aa49d;hpb=c0514526561e5fde6db765e294c19e0aaee15e1e;p=user%2Fhenk%2Fcode%2Finspircd.git diff --git a/src/coremods/core_dns.cpp b/src/coremods/core_dns.cpp index 1e7f6afca..dbfb0b582 100644 --- a/src/coremods/core_dns.cpp +++ b/src/coremods/core_dns.cpp @@ -1,8 +1,10 @@ /* * InspIRCd -- Internet Relay Chat Daemon * - * Copyright (C) 2013 Adam - * Copyright (C) 2003-2013 Anope Team + * Copyright (C) 2019 Robby + * Copyright (C) 2015, 2017-2020 Sadie Powell + * Copyright (C) 2013-2016 Attila Molnar + * Copyright (C) 2013, 2015-2016 Adam * * This file is part of InspIRCd. InspIRCd is free software: you can * redistribute it and/or modify it under the terms of the GNU General Public @@ -36,15 +38,10 @@ namespace DNS using namespace DNS; -/** A full packet sent or recieved to/from the nameserver +/** A full packet sent or received to/from the nameserver */ class Packet : public Query { - static bool IsValidName(const std::string& name) - { - return (name.find_first_not_of("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.-") == std::string::npos); - } - void PackName(unsigned char* output, unsigned short output_size, unsigned short& pos, const std::string& name) { if (pos + name.length() + 2 > output_size) @@ -154,7 +151,7 @@ class Packet : public Query record.ttl = (input[pos] << 24) | (input[pos + 1] << 16) | (input[pos + 2] << 8) | input[pos + 3]; pos += 4; - //record.rdlength = input[pos] << 8 | input[pos + 1]; + uint16_t rdlength = input[pos] << 8 | input[pos + 1]; pos += 2; switch (record.type) @@ -195,11 +192,24 @@ class Packet : public Query case QUERY_PTR: { record.rdata = this->UnpackName(input, input_size, pos); - if (!IsValidName(record.rdata)) + if (!InspIRCd::IsHost(record.rdata)) throw Exception("Invalid name"); // XXX: Causes the request to time out break; } + case QUERY_TXT: + { + if (pos + rdlength > input_size) + throw Exception("Unable to unpack txt resource record"); + + record.rdata = std::string(reinterpret_cast(input + pos), rdlength); + pos += rdlength; + + if (record.rdata.find_first_of("\r\n\0", 0, 3) != std::string::npos) + throw Exception("Invalid character in txt record"); + + break; + } default: break; } @@ -338,6 +348,7 @@ class MyManager : public Manager, public Timer, public EventHandler cache_map cache; irc::sockets::sockaddrs myserver; + bool unloading; /** Maximum number of entries in cache */ @@ -402,6 +413,7 @@ class MyManager : public Manager, public Timer, public EventHandler DNS::Request* requests[MAX_REQUEST_ID+1]; MyManager(Module* c) : Manager(c), Timer(5*60, true) + , unloading(false) { for (unsigned int i = 0; i <= MAX_REQUEST_ID; ++i) requests[i] = NULL; @@ -410,13 +422,17 @@ class MyManager : public Manager, public Timer, public EventHandler ~MyManager() { + // Ensure Process() will fail for new requests + Close(); + unloading = true; + for (unsigned int i = 0; i <= MAX_REQUEST_ID; ++i) { DNS::Request* request = requests[i]; if (!request) continue; - Query rr(*request); + Query rr(request->question); rr.error = ERROR_UNKNOWN; request->OnError(&rr); @@ -424,9 +440,33 @@ class MyManager : public Manager, public Timer, public EventHandler } } - void Process(DNS::Request* req) + void Close() + { + // Shutdown the socket if it exists. + if (HasFd()) + { + SocketEngine::Shutdown(this, 2); + SocketEngine::Close(this); + } + + // Remove all entries from the cache. + cache.clear(); + } + + void Process(DNS::Request* req) CXX11_OVERRIDE { - ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Processing request to lookup " + req->name + " of type " + ConvToStr(req->type) + " to " + this->myserver.addr()); + if ((unloading) || (req->creator->dying)) + throw Exception("Module is being unloaded"); + + if (!HasFd()) + { + Query rr(req->question); + rr.error = ERROR_DISABLED; + req->OnError(&rr); + return; + } + + ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Processing request to lookup " + req->question.name + " of type " + ConvToStr(req->question.type) + " to " + this->myserver.addr()); /* Create an id */ unsigned int tries = 0; @@ -463,7 +503,7 @@ class MyManager : public Manager, public Timer, public EventHandler Packet p; p.flags = QUERYFLAGS_RD; p.id = req->id; - p.question = *req; + p.question = req->question; unsigned char buffer[524]; unsigned short len = p.Pack(buffer, sizeof(buffer)); @@ -479,22 +519,22 @@ class MyManager : public Manager, public Timer, public EventHandler } // Update name in the original request so question checking works for PTR queries - req->name = p.question.name; + req->question.name = p.question.name; - if (SocketEngine::SendTo(this, buffer, len, 0, &this->myserver.sa, this->myserver.sa_size()) != len) + if (SocketEngine::SendTo(this, buffer, len, 0, this->myserver) != len) throw Exception("DNS: Unable to send query"); // Add timer for timeout ServerInstance->Timers.AddTimer(req); } - void RemoveRequest(DNS::Request* req) + void RemoveRequest(DNS::Request* req) CXX11_OVERRIDE { if (requests[req->id] == req) requests[req->id] = NULL; } - std::string GetErrorStr(Error e) + std::string GetErrorStr(Error e) CXX11_OVERRIDE { switch (e) { @@ -515,6 +555,8 @@ class MyManager : public Manager, public Timer, public EventHandler case ERROR_DOMAIN_NOT_FOUND: case ERROR_NO_RECORDS: return "Domain not found"; + case ERROR_DISABLED: + return "DNS lookups are disabled"; case ERROR_NONE: case ERROR_UNKNOWN: default: @@ -522,6 +564,25 @@ class MyManager : public Manager, public Timer, public EventHandler } } + std::string GetTypeStr(QueryType qt) CXX11_OVERRIDE + { + switch (qt) + { + case QUERY_A: + return "A"; + case QUERY_AAAA: + return "AAAA"; + case QUERY_CNAME: + return "CNAME"; + case QUERY_PTR: + return "PTR"; + case QUERY_TXT: + return "TXT"; + default: + return "UNKNOWN"; + } + } + void OnEventHandlerError(int errcode) CXX11_OVERRIDE { ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "UDP socket got an error event"); @@ -568,7 +629,7 @@ class MyManager : public Manager, public Timer, public EventHandler return; } - if (static_cast(*request) != recv_packet.question) + if (request->question != recv_packet.question) { // This can happen under high latency, drop it silently, do not fail the request ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Received an answer that isn't for a question we asked"); @@ -631,7 +692,7 @@ class MyManager : public Manager, public Timer, public EventHandler } else { - ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Lookup complete for " + request->name); + ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Lookup complete for " + request->question.name); ServerInstance->stats.DnsGood++; request->OnLookupComplete(&recv_packet); this->AddCache(recv_packet); @@ -643,40 +704,38 @@ class MyManager : public Manager, public Timer, public EventHandler delete request; } - bool Tick(time_t now) + bool Tick(time_t now) CXX11_OVERRIDE { - ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "cache: purging DNS cache"); - + unsigned long expired = 0; for (cache_map::iterator it = this->cache.begin(); it != this->cache.end(); ) { const Query& query = it->second; if (IsExpired(query, now)) + { + expired++; this->cache.erase(it++); + } else ++it; } + + if (expired) + ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "cache: purged %lu expired DNS entries", expired); + return true; } void Rehash(const std::string& dnsserver, std::string sourceaddr, unsigned int sourceport) { - if (this->GetFd() > -1) - { - SocketEngine::Shutdown(this, 2); - SocketEngine::Close(this); - - /* Remove expired entries from the cache */ - this->Tick(ServerInstance->Time()); - } - irc::sockets::aptosa(dnsserver, DNS::PORT, myserver); /* Initialize mastersocket */ - int s = socket(myserver.sa.sa_family, SOCK_DGRAM, 0); + Close(); + int s = socket(myserver.family(), SOCK_DGRAM, 0); this->SetFd(s); /* Have we got a socket? */ - if (this->GetFd() != -1) + if (this->HasFd()) { SocketEngine::SetReuse(s); SocketEngine::NonBlocking(s); @@ -685,9 +744,9 @@ class MyManager : public Manager, public Timer, public EventHandler if (sourceaddr.empty()) { // set a sourceaddr for irc::sockets::aptosa() based on the servers af type - if (myserver.sa.sa_family == AF_INET) + if (myserver.family() == AF_INET) sourceaddr = "0.0.0.0"; - else if (myserver.sa.sa_family == AF_INET6) + else if (myserver.family() == AF_INET6) sourceaddr = "::"; } irc::sockets::aptosa(sourceaddr, sourceport, bindto); @@ -706,7 +765,7 @@ class MyManager : public Manager, public Timer, public EventHandler this->SetFd(-1); } - if (bindto.sa.sa_family != myserver.sa.sa_family) + if (bindto.family() != myserver.family()) ServerInstance->Logs->Log(MODNAME, LOG_SPARSE, "Nameserver address family differs from source address family - hostnames might not resolve"); } else @@ -727,7 +786,7 @@ class ModuleDNS : public Module { #ifdef _WIN32 // attempt to look up their nameserver from the system - ServerInstance->Logs->Log("CONFIG", LOG_DEFAULT, "WARNING: not defined, attempting to find a working server in the system settings..."); + ServerInstance->Logs->Log(MODNAME, LOG_DEFAULT, "WARNING: not defined, attempting to find a working server in the system settings..."); PFIXED_INFO pFixedInfo; DWORD dwBufferSize = sizeof(FIXED_INFO); @@ -751,15 +810,15 @@ class ModuleDNS : public Module if (!DNSServer.empty()) { - ServerInstance->Logs->Log("CONFIG", LOG_DEFAULT, " set to '%s' as first active resolver in the system settings.", DNSServer.c_str()); + ServerInstance->Logs->Log(MODNAME, LOG_DEFAULT, " set to '%s' as first active resolver in the system settings.", DNSServer.c_str()); return; } } - ServerInstance->Logs->Log("CONFIG", LOG_DEFAULT, "No viable nameserver found! Defaulting to nameserver '127.0.0.1'!"); + ServerInstance->Logs->Log(MODNAME, LOG_DEFAULT, "No viable nameserver found! Defaulting to nameserver '127.0.0.1'!"); #else // attempt to look up their nameserver from /etc/resolv.conf - ServerInstance->Logs->Log("CONFIG", LOG_DEFAULT, "WARNING: not defined, attempting to find working server in /etc/resolv.conf..."); + ServerInstance->Logs->Log(MODNAME, LOG_DEFAULT, "WARNING: not defined, attempting to find working server in /etc/resolv.conf..."); std::ifstream resolv("/etc/resolv.conf"); @@ -770,13 +829,13 @@ class ModuleDNS : public Module resolv >> DNSServer; if (DNSServer.find_first_not_of("0123456789.") == std::string::npos || DNSServer.find_first_not_of("0123456789ABCDEFabcdef:") == std::string::npos) { - ServerInstance->Logs->Log("CONFIG", LOG_DEFAULT, " set to '%s' as first resolver in /etc/resolv.conf.",DNSServer.c_str()); + ServerInstance->Logs->Log(MODNAME, LOG_DEFAULT, " set to '%s' as first resolver in /etc/resolv.conf.",DNSServer.c_str()); return; } } } - ServerInstance->Logs->Log("CONFIG", LOG_DEFAULT, "/etc/resolv.conf contains no viable nameserver entries! Defaulting to nameserver '127.0.0.1'!"); + ServerInstance->Logs->Log(MODNAME, LOG_DEFAULT, "/etc/resolv.conf contains no viable nameserver entries! Defaulting to nameserver '127.0.0.1'!"); #endif DNSServer = "127.0.0.1"; } @@ -789,14 +848,26 @@ class ModuleDNS : public Module void ReadConfig(ConfigStatus& status) CXX11_OVERRIDE { - std::string oldserver = DNSServer; - const std::string oldip = SourceIP; - const unsigned int oldport = SourcePort; - ConfigTag* tag = ServerInstance->Config->ConfValue("dns"); + if (!tag->getBool("enabled", true)) + { + // Clear these so they get reset if DNS is enabled again. + DNSServer.clear(); + SourceIP.clear(); + SourcePort = 0; + + this->manager.Close(); + return; + } + + const std::string oldserver = DNSServer; DNSServer = tag->getString("server"); + + const std::string oldip = SourceIP; SourceIP = tag->getString("sourceip"); - SourcePort = tag->getInt("sourceport", 0, 0, 65535); + + const unsigned int oldport = SourcePort; + SourcePort = tag->getUInt("sourceport", 0, 0, UINT16_MAX); if (DNSServer.empty()) FindDNSServer(); @@ -805,7 +876,7 @@ class ModuleDNS : public Module this->manager.Rehash(DNSServer, SourceIP, SourcePort); } - void OnUnloadModule(Module* mod) + void OnUnloadModule(Module* mod) CXX11_OVERRIDE { for (unsigned int i = 0; i <= MAX_REQUEST_ID; ++i) { @@ -815,7 +886,7 @@ class ModuleDNS : public Module if (req->creator == mod) { - Query rr(*req); + Query rr(req->question); rr.error = ERROR_UNLOADED; req->OnError(&rr); @@ -824,9 +895,9 @@ class ModuleDNS : public Module } } - Version GetVersion() + Version GetVersion() CXX11_OVERRIDE { - return Version("DNS support", VF_CORE|VF_VENDOR); + return Version("Provides support for DNS lookups", VF_CORE|VF_VENDOR); } };