89 lines
2.0 KiB
JavaScript
89 lines
2.0 KiB
JavaScript
'use strict';
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var native = module.exports;
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var promisify = require('util').promisify;
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var resolveTxt = promisify(require('dns').resolveTxt);
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var crypto = require('crypto');
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native._canCheck = function(me) {
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me._canCheck = {};
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me._canCheck['http-01'] = true;
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me._canCheck['dns-01'] = true;
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return Promise.resolve();
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};
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native._dns01 = function(me, ch) {
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// TODO use digd.js
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return resolveTxt(ch.dnsHost).then(function(records) {
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return {
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answer: records.map(function(rr) {
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return {
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data: rr
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};
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})
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};
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});
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};
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native._http01 = function(me, ch) {
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return new me.request({
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url: ch.challengeUrl
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}).then(function(resp) {
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return resp.body;
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});
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};
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// the hashcash here is for browser parity only
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// basically we ask the client to find a needle in a haystack
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// (very similar to CloudFlare's api protection)
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native._hashcash = function(ch) {
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if (!ch || !ch.nonce) {
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ch = { nonce: 'xxx' };
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}
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return Promise.resolve()
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.then(function() {
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// only get easy answers
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var len = ch.needle.length;
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var start = ch.start || 0;
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var end = ch.end || Math.ceil(len / 2);
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var window = parseInt(end - start, 10) || 0;
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var maxLen = 6;
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var maxTries = Math.pow(2, maxLen * 8);
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if (
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len > maxLen ||
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window < Math.ceil(len / 2) ||
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ch.needle.toLowerCase() !== ch.needle ||
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ch.alg !== 'SHA-256'
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) {
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// bail unless the server is issuing very easy challenges
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throw new Error('possible and easy answers only, please');
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}
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var haystack;
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var i;
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var answer;
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var needle = Buffer.from(ch.needle, 'hex');
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for (i = 0; i < maxTries; i += 1) {
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answer = i.toString(16);
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if (answer.length % 2) {
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answer = '0' + answer;
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}
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haystack = crypto
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.createHash('sha256')
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.update(Buffer.from(ch.nonce + answer, 'hex'))
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.digest()
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.slice(ch.start, ch.end);
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if (-1 !== haystack.indexOf(needle)) {
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return ch.nonce + ':' + answer;
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}
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}
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return ch.nonce + ':xxx';
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})
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.catch(function() {
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//console.log('[debug]', err);
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// ignore any error
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return ch.nonce + ':xxx';
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});
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};
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