acme.js/server.js

140 lines
4.8 KiB
JavaScript

'use strict';
var crypto = require('crypto');
//var dnsjs = require('dns-suite');
var dig = require('dig.js/dns-request');
var request = require('util').promisify(require('@root/request'));
var express = require('express');
var app = express();
var nameservers = require('dns').getServers();
var index = crypto.randomBytes(2).readUInt16BE(0) % nameservers.length;
var nameserver = nameservers[index];
app.use('/', express.static(__dirname));
app.use('/api', express.json());
app.get('/api/dns/:domain', function (req, res, next) {
var domain = req.params.domain;
var casedDomain = domain.toLowerCase().split('').map(function (ch) {
// dns0x20 takes advantage of the fact that the binary operation for toUpperCase is
// ch = ch | 0x20;
return Math.round(Math.random()) % 2 ? ch : ch.toUpperCase();
}).join('');
var typ = req.query.type;
var query = {
header: {
id: crypto.randomBytes(2).readUInt16BE(0)
, qr: 0
, opcode: 0
, aa: 0 // Authoritative-Only
, tc: 0 // NA
, rd: 1 // Recurse
, ra: 0 // NA
, rcode: 0 // NA
}
, question: [
{ name: casedDomain
//, type: typ || 'A'
, typeName: typ || 'A'
, className: 'IN'
}
]
};
var opts = {
onError: function (err) {
next(err);
}
, onMessage: function (packet) {
var fail0x20;
if (packet.id !== query.id) {
console.error('[SECURITY] ignoring packet for \'' + packet.question[0].name + '\' due to mismatched id');
console.error(packet);
return;
}
packet.question.forEach(function (q) {
// if (-1 === q.name.lastIndexOf(cli.casedQuery))
if (q.name !== casedDomain) {
fail0x20 = q.name;
}
});
[ 'question', 'answer', 'authority', 'additional' ].forEach(function (group) {
(packet[group]||[]).forEach(function (a) {
var an = a.name;
var i = domain.toLowerCase().lastIndexOf(a.name.toLowerCase()); // answer is something like ExAMPle.cOM and query was wWw.ExAMPle.cOM
var j = a.name.toLowerCase().lastIndexOf(domain.toLowerCase()); // answer is something like www.ExAMPle.cOM and query was ExAMPle.cOM
// it's important to note that these should only relpace changes in casing that we expected
// any abnormalities should be left intact to go "huh?" about
// TODO detect abnormalities?
if (-1 !== i) {
// "EXamPLE.cOm".replace("wWw.EXamPLE.cOm".substr(4), "www.example.com".substr(4))
a.name = a.name.replace(casedDomain.substr(i), domain.substr(i));
} else if (-1 !== j) {
// "www.example.com".replace("EXamPLE.cOm", "example.com")
a.name = a.name.substr(0, j) + a.name.substr(j).replace(casedDomain, domain);
}
// NOTE: right now this assumes that anything matching the query matches all the way to the end
// it does not handle the case of a record for example.com.uk being returned in response to a query for www.example.com correctly
// (but I don't think it should need to)
if (a.name.length !== an.length) {
console.error("[ERROR] question / answer mismatch: '" + an + "' != '" + a.length + "'");
console.error(a);
}
});
});
if (fail0x20) {
console.warn(";; Warning: DNS 0x20 security not implemented (or packet spoofed). Queried '"
+ casedDomain + "' but got response for '" + fail0x20 + "'.");
return;
}
res.send({
header: packet.header
, question: packet.question
, answer: packet.answer
, authority: packet.authority
, additional: packet.additional
, edns_options: packet.edns_options
});
}
, onListening: function () {}
, onSent: function (/*res*/) { }
, onTimeout: function (res) {
console.error('dns timeout:', res);
next(new Error("DNS timeout - no response"));
}
, onClose: function () { }
//, mdns: cli.mdns
, nameserver: nameserver
, port: 53
, timeout: 2000
};
dig.resolveJson(query, opts);
});
app.get('/api/http', function (req, res) {
var url = req.query.url;
return request({ method: 'GET', url: url }).then(function (resp) {
res.send(resp.body);
});
});
app.get('/api/_acme_api_', function (req, res) {
res.send({ success: true });
});
module.exports = app;
if (require.main === module) {
// curl -L http://localhost:3000/api/dns/example.com?type=A
console.info("Listening on localhost:3000");
app.listen(3000);
console.info("Try this:");
console.info("\tcurl -L 'http://localhost:3000/api/_acme_api_/'");
console.info("\tcurl -L 'http://localhost:3000/api/dns/example.com?type=A'");
console.info("\tcurl -L 'http://localhost:3000/api/http/?url=https://example.com'");
}