tlsSocket.remoteAddress = 'x';

aj@ubuntu-512mb-nyc1-01:~/tunnel$ node crash.js
listening on 3001
r undefined
s ::ffff:127.0.0.1
t ::ffff:127.0.0.1
FATAL ERROR: v8::ToLocalChecked Empty MaybeLocal.
 1: node::Abort() [node]
 2: 0x8d04bc [node]
 3: v8::Utils::ReportApiFailure(char const*, char const*) [node]
 4: node::TLSWrap::OnStreamRead(long, uv_buf_t const&) [node]
 5: node::JSStream::ReadBuffer(v8::FunctionCallbackInfo<v8::Value> const&) [node]
 6: v8::internal::FunctionCallbackArguments::Call(void (*)(v8::FunctionCallbackInfo<v8::Value> const&)) [node]
 7: 0xb17d2c [node]
 8: v8::internal::Builtin_HandleApiCall(int, v8::internal::Object**, v8::internal::Isolate*) [node]
 9: 0x6670cd042fd
Aborted (core dumped)

(function () {
  'use strict';

  var net = require('net');
  var tls = require('tls');
  var hostname = 'local.test.ppl.family';
  var tlsOpts = {
    key: require('fs').readFileSync('./privkey.pem')
  , cert: require('fs').readFileSync('./fullchain.pem')
  };
  var Duplex = require('stream').Duplex;
  var WebSocket = require('ws');

  var tls3000 = tls.createServer(tlsOpts, function (tlsSocket) {
    console.log('r', tlsSocket.remoteAddress);
    console.log('s', tlsSocket._handle._parentWrap._handle.owner.stream.remoteAddress);
    tlsSocket._remoteAddress = tlsSocket._handle._parentWrap._handle.owner.stream.remoteAddress;
    console.log('t', tlsSocket._remoteAddress);
    tlsSocket.remoteAddress = 'x'; // causes core dump
    console.log('u', tlsSocket.remoteAddress);
  });

  var Dup = {
    write: function (chunk, encoding, cb) {
      //console.log('_write', chunk.byteLength);
      this.__my_socket.write(chunk, encoding);
      cb();
    }
  , read: function (size) {
      //console.log('_read');
      var x = this.__my_socket.read(size);
      if (x) {
        console.log('_read', size);
        this.push(x);
      }
    }
  };

  function connectHttps(servername, socket) {
    var myDuplex = new Duplex();

    myDuplex.__my_socket = socket;
    myDuplex._write = Dup.write;
    myDuplex._read = Dup.read;
    myDuplex.remoteFamily = socket.remoteFamily;
    myDuplex.remoteAddress = socket.remoteAddress;
    myDuplex.remotePort = socket.remotePort;
    myDuplex.localFamily = socket.localFamily;
    myDuplex.localAddress = socket.localAddress;
    myDuplex.localPort = socket.localPort;

    tls3000.emit('connection', myDuplex);

    socket.on('data', function (chunk) {
      myDuplex.push(chunk);
    });
  }

  var tcp3000 = net.createServer();
  tcp3000.listen(3001, function () {
    console.log('listening on 3001');

    var wstunneler = new WebSocket('wss://' + hostname + ':3001/?access_token=xyz', { rejectUnauthorized: false });
    wstunneler.on('open', function () {
      console.log('ws open');
    });
  });

  tcp3000.on('connection', function (socket) {
    socket.once('data', function (firstChunk) {
      connectHttps(null, socket);
      socket.unshift(firstChunk);
    });

  });
}());