9129469235

Committed 17 May 2024 02:01PM UTC coverage: 62.995% (+1.5%) from 61.544%

Build # 9129469235

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Commit Message

Merge pull request #14186 from Habbie/backport-14047-to-auth-4.9.x

auth 4.9 dnsproxy: fix build on s390x

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61.47

/pdns/dnsproxy.cc

/*
 * This file is part of PowerDNS or dnsdist.
 * Copyright -- PowerDNS.COM B.V. and its contributors
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * In addition, for the avoidance of any doubt, permission is granted to
 * link this program with OpenSSL and to (re)distribute the binaries
 * produced as the result of such linking.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <sys/types.h>
#include <thread>

#include "packetcache.hh"
#include "utility.hh"
#include "dnsproxy.hh"
#include "pdnsexception.hh"
#include "dns.hh"
#include "logger.hh"
#include "statbag.hh"
#include "dns_random.hh"
#include "stubresolver.hh"
#include "arguments.hh"
#include "threadname.hh"
#include "ednsoptions.hh"
#include "ednssubnet.hh"

extern StatBag S;

DNSProxy::DNSProxy(const string& remote) :
  d_xor(dns_random_uint16())
{
  d_resanswers = S.getPointer("recursing-answers");
  d_resquestions = S.getPointer("recursing-questions");
  d_udpanswers = S.getPointer("udp-answers");

  vector<string> addresses;
  stringtok(addresses, remote, " ,\t");
  d_remote = ComboAddress(addresses[0], 53);

  if ((d_sock = socket(d_remote.sin4.sin_family, SOCK_DGRAM, 0)) < 0) {
    throw PDNSException(string("socket: ") + stringerror());
  }

  ComboAddress local;
  if (d_remote.sin4.sin_family == AF_INET) {
    local = ComboAddress("0.0.0.0");
  }
  else {
    local = ComboAddress("::");
  }

  unsigned int attempts = 0;
  for (; attempts < 10; attempts++) {
    local.sin4.sin_port = htons(10000 + dns_random(50000));

    if (::bind(d_sock, (struct sockaddr*)&local, local.getSocklen()) >= 0) { // NOLINT(cppcoreguidelines-pro-type-cstyle-cast)
      break;
    }
  }
  if (attempts == 10) {
    closesocket(d_sock);
    d_sock = -1;
    throw PDNSException(string("binding dnsproxy socket: ") + stringerror());
  }

  if (connect(d_sock, (sockaddr*)&d_remote, d_remote.getSocklen()) < 0) { // NOLINT(cppcoreguidelines-pro-type-cstyle-cast)
    throw PDNSException("Unable to UDP connect to remote nameserver " + d_remote.toStringWithPort() + ": " + stringerror());
  }

  g_log << Logger::Error << "DNS Proxy launched, local port " << ntohs(local.sin4.sin_port) << ", remote " << d_remote.toStringWithPort() << endl;
}

void DNSProxy::go()
{
  std::thread proxythread([this]() { mainloop(); });
  proxythread.detach();
}

//! look up qname target with r->qtype, plonk it in the answer section of 'r' with name aname
bool DNSProxy::completePacket(std::unique_ptr<DNSPacket>& reply, const DNSName& target, const DNSName& aname, const uint8_t scopeMask)
{
  string ECSOptionStr;

  if (reply->hasEDNSSubnet()) {
    DLOG(g_log << "dnsproxy::completePacket: Parsed edns source: " << reply->d_eso.source.toString() << ", scope: " << reply->d_eso.scope.toString() << ", family = " << reply->d_eso.scope.getNetwork().sin4.sin_family << endl);
    ECSOptionStr = makeEDNSSubnetOptsString(reply->d_eso);
    DLOG(g_log << "from dnsproxy::completePacket: Creating ECS option string " << makeHexDump(ECSOptionStr) << endl);
  }

  if (reply->d_tcp) {
    vector<DNSZoneRecord> ips;
    int ret1 = 0;
    int ret2 = 0;
    // rip out edns info here, pass it to the stubDoResolve
    if (reply->qtype == QType::A || reply->qtype == QType::ANY) {
      ret1 = stubDoResolve(target, QType::A, ips, reply->hasEDNSSubnet() ? &reply->d_eso : nullptr);
    }
    if (reply->qtype == QType::AAAA || reply->qtype == QType::ANY) {
      ret2 = stubDoResolve(target, QType::AAAA, ips, reply->hasEDNSSubnet() ? &reply->d_eso : nullptr);
    }

    if (ret1 != RCode::NoError || ret2 != RCode::NoError) {
      g_log << Logger::Error << "Error resolving for " << aname << " ALIAS " << target << " over UDP, original query came in over TCP";
      if (ret1 != RCode::NoError) {
        g_log << Logger::Error << ", A-record query returned " << RCode::to_s(ret1);
      }
      if (ret2 != RCode::NoError) {
        g_log << Logger::Error << ", AAAA-record query returned " << RCode::to_s(ret2);
      }
      g_log << Logger::Error << ", returning SERVFAIL" << endl;
      reply->clearRecords();
      reply->setRcode(RCode::ServFail);
    }
    else {
      for (auto& ip : ips) { // NOLINT(readability-identifier-length)
        ip.dr.d_name = aname;
        reply->addRecord(std::move(ip));
      }
    }

    uint16_t len = htons(reply->getString().length());
    string buffer((const char*)&len, 2);
    buffer.append(reply->getString());
    writen2WithTimeout(reply->getSocket(), buffer.c_str(), buffer.length(), timeval{::arg().asNum("tcp-idle-timeout"), 0});

    return true;
  }

  uint16_t id;
  uint16_t qtype = reply->qtype.getCode();
  {
    auto conntrack = d_conntrack.lock();
    id = getID_locked(*conntrack);

    ConntrackEntry ce;
    ce.id = reply->d.id;
    ce.remote = reply->d_remote;
    ce.outsock = reply->getSocket();
    ce.created = time(nullptr);
    ce.qtype = reply->qtype.getCode();
    ce.qname = target;
    ce.anyLocal = reply->d_anyLocal;
    ce.complete = std::move(reply);
    ce.aname = aname;
    ce.anameScopeMask = scopeMask;
    (*conntrack)[id] = std::move(ce);
  }

  vector<uint8_t> packet;
  DNSPacketWriter pw(packet, target, qtype);
  pw.getHeader()->rd = true;
  pw.getHeader()->id = id ^ d_xor;
  // Add EDNS Subnet if the client sent one - issue #5469
  if (!ECSOptionStr.empty()) {
    DLOG(g_log << "from dnsproxy::completePacket: adding ECS option string to packet options " << makeHexDump(ECSOptionStr) << endl);
    DNSPacketWriter::optvect_t opts;
    opts.emplace_back(EDNSOptionCode::ECS, ECSOptionStr);
    pw.addOpt(512, 0, 0, opts);
    pw.commit();
  }

  if (send(d_sock, packet.data(), packet.size(), 0) < 0) { // zoom
    g_log << Logger::Error << "Unable to send a packet to our recursing backend: " << stringerror() << endl;
  }

  return true;
}

/** This finds us an unused or stale ID. Does not actually clean the contents */
int DNSProxy::getID_locked(map_t& conntrack)
{
  map_t::iterator iter;
  for (int n = 0;; ++n) { // NOLINT(readability-identifier-length)
    iter = conntrack.find(n);
    if (iter == conntrack.end()) {
      return n;
    }
    if (iter->second.created < time(nullptr) - 60) {
      if (iter->second.created != 0) {
        g_log << Logger::Warning << "Recursive query for remote " << iter->second.remote.toStringWithPort() << " with internal id " << n << " was not answered by backend within timeout, reusing id" << endl;
        iter->second.complete.reset();
        S.inc("recursion-unanswered");
      }
      return n;
    }
  }
}

void DNSProxy::mainloop()
{
  setThreadName("pdns/dnsproxy");
  try {
    char buffer[1500];
    ssize_t len;

    struct msghdr msgh;
    struct iovec iov;
    cmsgbuf_aligned cbuf;
    ComboAddress fromaddr;

    for (;;) {
      socklen_t fromaddrSize = sizeof(fromaddr);
      len = recvfrom(d_sock, &buffer[0], sizeof(buffer), 0, (struct sockaddr*)&fromaddr, &fromaddrSize); // answer from our backend  NOLINT(cppcoreguidelines-pro-type-cstyle-cast)
      if (len < (ssize_t)sizeof(dnsheader)) {
        if (len < 0) {
          g_log << Logger::Error << "Error receiving packet from recursor backend: " << stringerror() << endl;
        }
        else if (len == 0) {
          g_log << Logger::Error << "Error receiving packet from recursor backend, EOF" << endl;
        }
        else {
          g_log << Logger::Error << "Short packet from recursor backend, " << len << " bytes" << endl;
        }

        continue;
      }
      if (fromaddr != d_remote) {
        g_log << Logger::Error << "Got answer from unexpected host " << fromaddr.toStringWithPort() << " instead of our recursor backend " << d_remote.toStringWithPort() << endl;
        continue;
      }
      (*d_resanswers)++;
      (*d_udpanswers)++;
      dnsheader dHead{};
      memcpy(&dHead, &buffer[0], sizeof(dHead));
      {
        auto conntrack = d_conntrack.lock();
        if (BYTE_ORDER == BIG_ENDIAN) {
          // this is needed because spoof ID down below does not respect the native byteorder
          dHead.id = (256 * (uint16_t)buffer[1]) + (uint16_t)buffer[0];
        }

        auto iter = conntrack->find(dHead.id ^ d_xor);
        if (iter == conntrack->end()) {
          g_log << Logger::Error << "Discarding untracked packet from recursor backend with id " << (dHead.id ^ d_xor) << ". Conntrack table size=" << conntrack->size() << endl;
          continue;
        }
        if (iter->second.created == 0) {
          g_log << Logger::Error << "Received packet from recursor backend with id " << (dHead.id ^ d_xor) << " which is a duplicate" << endl;
          continue;
        }

        dHead.id = iter->second.id;
        memcpy(&buffer[0], &dHead, sizeof(dHead)); // commit spoofed id

        DNSPacket packet(false);
        packet.parse(&buffer[0], (size_t)len);

        if (packet.qtype.getCode() != iter->second.qtype || packet.qdomain != iter->second.qname) {
          g_log << Logger::Error << "Discarding packet from recursor backend with id " << (dHead.id ^ d_xor) << ", qname or qtype mismatch (" << packet.qtype.getCode() << " v " << iter->second.qtype << ", " << packet.qdomain << " v " << iter->second.qname << ")" << endl;
          continue;
        }

        /* Set up iov and msgh structures. */
        memset(&msgh, 0, sizeof(struct msghdr));
        string reply; // needs to be alive at time of sendmsg!
        MOADNSParser mdp(false, packet.getString());
        // update the EDNS options with info from the resolver - issue #5469
        // note that this relies on the ECS string encoder to use the source network, and only take the prefix length from scope
        iter->second.complete->d_eso.scope = packet.d_eso.scope;
        DLOG(g_log << "from dnsproxy::mainLoop: updated EDNS options from resolver EDNS source: " << iter->second.complete->d_eso.source.toString() << " EDNS scope: " << iter->second.complete->d_eso.scope.toString() << endl);

        if (mdp.d_header.rcode == RCode::NoError) {
          for (const auto& answer : mdp.d_answers) {
            if (answer.first.d_place == DNSResourceRecord::ANSWER || (answer.first.d_place == DNSResourceRecord::AUTHORITY && answer.first.d_type == QType::SOA)) {

              if (answer.first.d_type == iter->second.qtype || (iter->second.qtype == QType::ANY && (answer.first.d_type == QType::A || answer.first.d_type == QType::AAAA))) {
                DNSZoneRecord dzr;
                dzr.dr.d_name = iter->second.aname;
                dzr.dr.d_type = answer.first.d_type;
                dzr.dr.d_ttl = answer.first.d_ttl;
                dzr.dr.d_place = answer.first.d_place;
                dzr.dr.setContent(answer.first.getContent());
                iter->second.complete->addRecord(std::move(dzr));
              }
            }
          }

          iter->second.complete->setRcode(mdp.d_header.rcode);
        }
        else {
          g_log << Logger::Error << "Error resolving for " << iter->second.aname << " ALIAS " << iter->second.qname << " over UDP, " << QType(iter->second.qtype).toString() << "-record query returned " << RCode::to_s(mdp.d_header.rcode) << ", returning SERVFAIL" << endl;
          iter->second.complete->clearRecords();
          iter->second.complete->setRcode(RCode::ServFail);
        }
        reply = iter->second.complete->getString();
        iov.iov_base = (void*)reply.c_str();
        iov.iov_len = reply.length();
        iter->second.complete.reset();
        msgh.msg_iov = &iov;
        msgh.msg_iovlen = 1;
        msgh.msg_name = (struct sockaddr*)&iter->second.remote; // NOLINT(cppcoreguidelines-pro-type-cstyle-cast)
        msgh.msg_namelen = iter->second.remote.getSocklen();
        msgh.msg_control = nullptr;

        if (iter->second.anyLocal) {
          addCMsgSrcAddr(&msgh, &cbuf, iter->second.anyLocal.get_ptr(), 0);
        }
        if (sendmsg(iter->second.outsock, &msgh, 0) < 0) {
          int err = errno;
          g_log << Logger::Warning << "dnsproxy.cc: Error sending reply with sendmsg (socket=" << iter->second.outsock << "): " << stringerror(err) << endl;
        }
        iter->second.created = 0;
      }
    }
  }
  catch (PDNSException& ae) {
    g_log << Logger::Error << "Fatal error in DNS proxy: " << ae.reason << endl;
  }
  catch (std::exception& e) {
    g_log << Logger::Error << "Communicator thread died because of STL error: " << e.what() << endl;
  }
  catch (...) {
    g_log << Logger::Error << "Caught unknown exception." << endl;
  }
  g_log << Logger::Error << "Exiting because DNS proxy failed" << endl;
  _exit(1);
}

DNSProxy::~DNSProxy()
{
  if (d_sock > -1) {
    try {
      closesocket(d_sock);
    }
    catch (const PDNSException& e) {
    }
  }

  d_sock = -1;
}

1	/*
2	* This file is part of PowerDNS or dnsdist.
3	* Copyright -- PowerDNS.COM B.V. and its contributors
4	*
5	* This program is free software; you can redistribute it and/or modify
6	* it under the terms of version 2 of the GNU General Public License as
7	* published by the Free Software Foundation.
8	*
9	* In addition, for the avoidance of any doubt, permission is granted to
10	* link this program with OpenSSL and to (re)distribute the binaries
11	* produced as the result of such linking.
12	*
13	* This program is distributed in the hope that it will be useful,
14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16	* GNU General Public License for more details.
17	*
18	* You should have received a copy of the GNU General Public License
19	* along with this program; if not, write to the Free Software
20	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
21	*/
22	#ifdef HAVE_CONFIG_H
23	#include "config.h"
24	#endif
25
26	#include <sys/types.h>
27	#include <thread>
28
29	#include "packetcache.hh"
30	#include "utility.hh"
31	#include "dnsproxy.hh"
32	#include "pdnsexception.hh"
33	#include "dns.hh"
34	#include "logger.hh"
35	#include "statbag.hh"
36	#include "dns_random.hh"
37	#include "stubresolver.hh"
38	#include "arguments.hh"
39	#include "threadname.hh"
40	#include "ednsoptions.hh"
41	#include "ednssubnet.hh"
42
43	extern StatBag S;
44
45	DNSProxy::DNSProxy(const string& remote) :
46	d_xor(dns_random_uint16())
47	{	37✔
48	d_resanswers = S.getPointer("recursing-answers");	37✔
49	d_resquestions = S.getPointer("recursing-questions");	37✔
50	d_udpanswers = S.getPointer("udp-answers");	37✔
51
52	vector<string> addresses;	37✔
53	stringtok(addresses, remote, " ,\t");	37✔
54	d_remote = ComboAddress(addresses[0], 53);	37✔
55
56	if ((d_sock = socket(d_remote.sin4.sin_family, SOCK_DGRAM, 0)) < 0) {	37!
57	throw PDNSException(string("socket: ") + stringerror());	×
58	}	×
59
60	ComboAddress local;	37✔
61	if (d_remote.sin4.sin_family == AF_INET) {	37!
62	local = ComboAddress("0.0.0.0");	37✔
63	}	37✔
64	else {	×
65	local = ComboAddress("::");	×
66	}	×
67
68	unsigned int attempts = 0;	37✔
69	for (; attempts < 10; attempts++) {	37!
70	local.sin4.sin_port = htons(10000 + dns_random(50000));	37✔
71
72	if (::bind(d_sock, (struct sockaddr*)&local, local.getSocklen()) >= 0) { // NOLINT(cppcoreguidelines-pro-type-cstyle-cast)	37!
73	break;	37✔
74	}	37✔
75	}	37✔
76	if (attempts == 10) {	37!
77	closesocket(d_sock);	×
78	d_sock = -1;	×
79	throw PDNSException(string("binding dnsproxy socket: ") + stringerror());	×
80	}	×
81
82	if (connect(d_sock, (sockaddr*)&d_remote, d_remote.getSocklen()) < 0) { // NOLINT(cppcoreguidelines-pro-type-cstyle-cast)	37!
83	throw PDNSException("Unable to UDP connect to remote nameserver " + d_remote.toStringWithPort() + ": " + stringerror());	×
84	}	×
85
86	g_log << Logger::Error << "DNS Proxy launched, local port " << ntohs(local.sin4.sin_port) << ", remote " << d_remote.toStringWithPort() << endl;	37✔
87	}	37✔
88
89	void DNSProxy::go()
90	{	37✔
91	std::thread proxythread([this]() { mainloop(); });	37✔
92	proxythread.detach();	37✔
93	}	37✔
94
95	//! look up qname target with r->qtype, plonk it in the answer section of 'r' with name aname
96	bool DNSProxy::completePacket(std::unique_ptr<DNSPacket>& reply, const DNSName& target, const DNSName& aname, const uint8_t scopeMask)
97	{	301✔
98	string ECSOptionStr;	301✔
99
100	if (reply->hasEDNSSubnet()) {	301!
101	DLOG(g_log << "dnsproxy::completePacket: Parsed edns source: " << reply->d_eso.source.toString() << ", scope: " << reply->d_eso.scope.toString() << ", family = " << reply->d_eso.scope.getNetwork().sin4.sin_family << endl);	×
102	ECSOptionStr = makeEDNSSubnetOptsString(reply->d_eso);	×
103	DLOG(g_log << "from dnsproxy::completePacket: Creating ECS option string " << makeHexDump(ECSOptionStr) << endl);	×
104	}	×
105
106	if (reply->d_tcp) {	301✔
107	vector<DNSZoneRecord> ips;	114✔
108	int ret1 = 0;	114✔
109	int ret2 = 0;	114✔
110	// rip out edns info here, pass it to the stubDoResolve
111	if (reply->qtype == QType::A \|\| reply->qtype == QType::ANY) {	114!
112	ret1 = stubDoResolve(target, QType::A, ips, reply->hasEDNSSubnet() ? &reply->d_eso : nullptr);	57!
113	}	57✔
114	if (reply->qtype == QType::AAAA \|\| reply->qtype == QType::ANY) {	114!
115	ret2 = stubDoResolve(target, QType::AAAA, ips, reply->hasEDNSSubnet() ? &reply->d_eso : nullptr);	57!
116	}	57✔
117
118	if (ret1 != RCode::NoError \|\| ret2 != RCode::NoError) {	114!
119	g_log << Logger::Error << "Error resolving for " << aname << " ALIAS " << target << " over UDP, original query came in over TCP";	×
120	if (ret1 != RCode::NoError) {	×
121	g_log << Logger::Error << ", A-record query returned " << RCode::to_s(ret1);	×
122	}	×
123	if (ret2 != RCode::NoError) {	×
124	g_log << Logger::Error << ", AAAA-record query returned " << RCode::to_s(ret2);	×
125	}	×
126	g_log << Logger::Error << ", returning SERVFAIL" << endl;	×
127	reply->clearRecords();	×
128	reply->setRcode(RCode::ServFail);	×
129	}	×
130	else {	114✔
131	for (auto& ip : ips) { // NOLINT(readability-identifier-length)	114✔
132	ip.dr.d_name = aname;	114✔
133	reply->addRecord(std::move(ip));	114✔
134	}	114✔
135	}	114✔
136
137	uint16_t len = htons(reply->getString().length());	114✔
138	string buffer((const char*)&len, 2);	114✔
139	buffer.append(reply->getString());	114✔
140	writen2WithTimeout(reply->getSocket(), buffer.c_str(), buffer.length(), timeval{::arg().asNum("tcp-idle-timeout"), 0});	114✔
141
142	return true;	114✔
143	}	114✔
144
145	uint16_t id;	187✔
146	uint16_t qtype = reply->qtype.getCode();	187✔
147	{	187✔
148	auto conntrack = d_conntrack.lock();	187✔
149	id = getID_locked(*conntrack);	187✔
150
151	ConntrackEntry ce;	187✔
152	ce.id = reply->d.id;	187✔
153	ce.remote = reply->d_remote;	187✔
154	ce.outsock = reply->getSocket();	187✔
155	ce.created = time(nullptr);	187✔
156	ce.qtype = reply->qtype.getCode();	187✔
157	ce.qname = target;	187✔
158	ce.anyLocal = reply->d_anyLocal;	187✔
159	ce.complete = std::move(reply);	187✔
160	ce.aname = aname;	187✔
161	ce.anameScopeMask = scopeMask;	187✔
162	(*conntrack)[id] = std::move(ce);	187✔
163	}	187✔
164
165	vector<uint8_t> packet;	187✔
166	DNSPacketWriter pw(packet, target, qtype);	187✔
167	pw.getHeader()->rd = true;	187✔
168	pw.getHeader()->id = id ^ d_xor;	187✔
169	// Add EDNS Subnet if the client sent one - issue #5469
170	if (!ECSOptionStr.empty()) {	187!
171	DLOG(g_log << "from dnsproxy::completePacket: adding ECS option string to packet options " << makeHexDump(ECSOptionStr) << endl);	×
172	DNSPacketWriter::optvect_t opts;	×
173	opts.emplace_back(EDNSOptionCode::ECS, ECSOptionStr);	×
174	pw.addOpt(512, 0, 0, opts);	×
175	pw.commit();	×
176	}	×
177
178	if (send(d_sock, packet.data(), packet.size(), 0) < 0) { // zoom	187!
179	g_log << Logger::Error << "Unable to send a packet to our recursing backend: " << stringerror() << endl;	×
180	}	×
181
182	return true;	187✔
183	}	301✔
184
185	/** This finds us an unused or stale ID. Does not actually clean the contents */
186	int DNSProxy::getID_locked(map_t& conntrack)
187	{	187✔
188	map_t::iterator iter;	187✔
189	for (int n = 0;; ++n) { // NOLINT(readability-identifier-length)	187✔
190	iter = conntrack.find(n);	187✔
191	if (iter == conntrack.end()) {	187✔
192	return n;	37✔
193	}	37✔
194	if (iter->second.created < time(nullptr) - 60) {	150!
195	if (iter->second.created != 0) {	150!
196	g_log << Logger::Warning << "Recursive query for remote " << iter->second.remote.toStringWithPort() << " with internal id " << n << " was not answered by backend within timeout, reusing id" << endl;	×
197	iter->second.complete.reset();	×
198	S.inc("recursion-unanswered");	×
199	}	×
200	return n;	150✔
201	}	150✔
202	}	150✔
203	}	187✔
204
205	void DNSProxy::mainloop()
206	{	37✔
207	setThreadName("pdns/dnsproxy");	37✔
208	try {	37✔
209	char buffer[1500];	37✔
210	ssize_t len;	37✔
211
212	struct msghdr msgh;	37✔
213	struct iovec iov;	37✔
214	cmsgbuf_aligned cbuf;	37✔
215	ComboAddress fromaddr;	37✔
216
217	for (;;) {	224✔
218	socklen_t fromaddrSize = sizeof(fromaddr);	224✔
219	len = recvfrom(d_sock, &buffer[0], sizeof(buffer), 0, (struct sockaddr*)&fromaddr, &fromaddrSize); // answer from our backend NOLINT(cppcoreguidelines-pro-type-cstyle-cast)	224✔
220	if (len < (ssize_t)sizeof(dnsheader)) {	224!
221	if (len < 0) {	×
222	g_log << Logger::Error << "Error receiving packet from recursor backend: " << stringerror() << endl;	×
223	}	×
224	else if (len == 0) {	×
225	g_log << Logger::Error << "Error receiving packet from recursor backend, EOF" << endl;	×
226	}	×
227	else {	×
228	g_log << Logger::Error << "Short packet from recursor backend, " << len << " bytes" << endl;	×
229	}	×
230
231	continue;	×
232	}	×
233	if (fromaddr != d_remote) {	224!
234	g_log << Logger::Error << "Got answer from unexpected host " << fromaddr.toStringWithPort() << " instead of our recursor backend " << d_remote.toStringWithPort() << endl;	×
235	continue;	×
236	}	×
237	(*d_resanswers)++;	224✔
238	(*d_udpanswers)++;	224✔
239	dnsheader dHead{};	224✔
240	memcpy(&dHead, &buffer[0], sizeof(dHead));	224✔
241	{	224✔
242	auto conntrack = d_conntrack.lock();	224✔
243	if (BYTE_ORDER == BIG_ENDIAN) {	224✔
244	// this is needed because spoof ID down below does not respect the native byteorder
NEW 245	dHead.id = (256 * (uint16_t)buffer[1]) + (uint16_t)buffer[0];	×
NEW 246	}	×
247
248	auto iter = conntrack->find(dHead.id ^ d_xor);	224✔
249	if (iter == conntrack->end()) {	224!
250	g_log << Logger::Error << "Discarding untracked packet from recursor backend with id " << (dHead.id ^ d_xor) << ". Conntrack table size=" << conntrack->size() << endl;	×
251	continue;	×
252	}	×
253	if (iter->second.created == 0) {	224!
254	g_log << Logger::Error << "Received packet from recursor backend with id " << (dHead.id ^ d_xor) << " which is a duplicate" << endl;	×
255	continue;	×
256	}	×
257
258	dHead.id = iter->second.id;	224✔
259	memcpy(&buffer[0], &dHead, sizeof(dHead)); // commit spoofed id	224✔
260
261	DNSPacket packet(false);	224✔
262	packet.parse(&buffer[0], (size_t)len);	224✔
263
264	if (packet.qtype.getCode() != iter->second.qtype \|\| packet.qdomain != iter->second.qname) {	224!
265	g_log << Logger::Error << "Discarding packet from recursor backend with id " << (dHead.id ^ d_xor) << ", qname or qtype mismatch (" << packet.qtype.getCode() << " v " << iter->second.qtype << ", " << packet.qdomain << " v " << iter->second.qname << ")" << endl;	×
266	continue;	×
267	}	×
268
269	/* Set up iov and msgh structures. */
270	memset(&msgh, 0, sizeof(struct msghdr));	224✔
271	string reply; // needs to be alive at time of sendmsg!	224✔
272	MOADNSParser mdp(false, packet.getString());	224✔
273	// update the EDNS options with info from the resolver - issue #5469
274	// note that this relies on the ECS string encoder to use the source network, and only take the prefix length from scope
275	iter->second.complete->d_eso.scope = packet.d_eso.scope;	224✔
276	DLOG(g_log << "from dnsproxy::mainLoop: updated EDNS options from resolver EDNS source: " << iter->second.complete->d_eso.source.toString() << " EDNS scope: " << iter->second.complete->d_eso.scope.toString() << endl);	224✔
277
278	if (mdp.d_header.rcode == RCode::NoError) {	224✔
279	for (const auto& answer : mdp.d_answers) {	187✔
280	if (answer.first.d_place == DNSResourceRecord::ANSWER \|\| (answer.first.d_place == DNSResourceRecord::AUTHORITY && answer.first.d_type == QType::SOA)) {	187!
281
282	if (answer.first.d_type == iter->second.qtype \|\| (iter->second.qtype == QType::ANY && (answer.first.d_type == QType::A \|\| answer.first.d_type == QType::AAAA))) {	187!
283	DNSZoneRecord dzr;	187✔
284	dzr.dr.d_name = iter->second.aname;	187✔
285	dzr.dr.d_type = answer.first.d_type;	187✔
286	dzr.dr.d_ttl = answer.first.d_ttl;	187✔
287	dzr.dr.d_place = answer.first.d_place;	187✔
288	dzr.dr.setContent(answer.first.getContent());	187✔
289	iter->second.complete->addRecord(std::move(dzr));	187✔
290	}	187✔
291	}	187✔
292	}	187✔
293
294	iter->second.complete->setRcode(mdp.d_header.rcode);	187✔
295	}	187✔
296	else {	37✔
297	g_log << Logger::Error << "Error resolving for " << iter->second.aname << " ALIAS " << iter->second.qname << " over UDP, " << QType(iter->second.qtype).toString() << "-record query returned " << RCode::to_s(mdp.d_header.rcode) << ", returning SERVFAIL" << endl;	37✔
298	iter->second.complete->clearRecords();	37✔
299	iter->second.complete->setRcode(RCode::ServFail);	37✔
300	}	37✔
301	reply = iter->second.complete->getString();	224✔
302	iov.iov_base = (void*)reply.c_str();	224✔
303	iov.iov_len = reply.length();	224✔
304	iter->second.complete.reset();	224✔
305	msgh.msg_iov = &iov;	224✔
306	msgh.msg_iovlen = 1;	224✔
307	msgh.msg_name = (struct sockaddr*)&iter->second.remote; // NOLINT(cppcoreguidelines-pro-type-cstyle-cast)	224✔
308	msgh.msg_namelen = iter->second.remote.getSocklen();	224✔
309	msgh.msg_control = nullptr;	224✔
310
311	if (iter->second.anyLocal) {	224!
312	addCMsgSrcAddr(&msgh, &cbuf, iter->second.anyLocal.get_ptr(), 0);	×
313	}	×
314	if (sendmsg(iter->second.outsock, &msgh, 0) < 0) {	224!
315	int err = errno;	×
316	g_log << Logger::Warning << "dnsproxy.cc: Error sending reply with sendmsg (socket=" << iter->second.outsock << "): " << stringerror(err) << endl;	×
317	}	×
318	iter->second.created = 0;	224✔
319	}	224✔
320	}	224✔
321	}	37✔
322	catch (PDNSException& ae) {	37✔
323	g_log << Logger::Error << "Fatal error in DNS proxy: " << ae.reason << endl;	×
324	}	×
325	catch (std::exception& e) {	37✔
326	g_log << Logger::Error << "Communicator thread died because of STL error: " << e.what() << endl;	×
327	}	×
328	catch (...) {	37✔
329	g_log << Logger::Error << "Caught unknown exception." << endl;	×
330	}	×
331	g_log << Logger::Error << "Exiting because DNS proxy failed" << endl;	37✔
332	_exit(1);	×
333	}	37✔
334
335	DNSProxy::~DNSProxy()
336	{	×
337	if (d_sock > -1) {	×
338	try {	×
339	closesocket(d_sock);	×
340	}	×
341	catch (const PDNSException& e) {	×
342	}	×
343	}	×
344
345	d_sock = -1;	×
346	}	×

PowerDNS / pdns / 9129469235

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