diff --git a/test/common/dns.js b/test/common/dns.js new file mode 100644 index 00000000000000..fb2f36ee750d87 --- /dev/null +++ b/test/common/dns.js @@ -0,0 +1,290 @@ +/* eslint-disable required-modules */ +'use strict'; + +// Naïve DNS parser/serializer. + +const assert = require('assert'); +const os = require('os'); + +const types = { + A: 1, + AAAA: 28, + NS: 2, + CNAME: 5, + SOA: 6, + PTR: 12, + MX: 15, + TXT: 16, + ANY: 255 +}; + +const classes = { + IN: 1 +}; + +function readDomainFromPacket(buffer, offset) { + assert.ok(offset < buffer.length); + const length = buffer[offset]; + if (length === 0) { + return { nread: 1, domain: '' }; + } else if ((length & 0xC0) === 0) { + offset += 1; + const chunk = buffer.toString('ascii', offset, offset + length); + // Read the rest of the domain. + const { nread, domain } = readDomainFromPacket(buffer, offset + length); + return { + nread: 1 + length + nread, + domain: domain ? `${chunk}.${domain}` : chunk + }; + } else { + // Pointer to another part of the packet. + assert.strictEqual(length & 0xC0, 0xC0); + // eslint-disable-next-line + const pointeeOffset = buffer.readUInt16BE(offset) &~ 0xC000; + return { + nread: 2, + domain: readDomainFromPacket(buffer, pointeeOffset) + }; + } +} + +function parseDNSPacket(buffer) { + assert.ok(buffer.length > 12); + + const parsed = { + id: buffer.readUInt16BE(0), + flags: buffer.readUInt16BE(2), + }; + + const counts = [ + ['questions', buffer.readUInt16BE(4)], + ['answers', buffer.readUInt16BE(6)], + ['authorityAnswers', buffer.readUInt16BE(8)], + ['additionalRecords', buffer.readUInt16BE(10)] + ]; + + let offset = 12; + for (const [ sectionName, count ] of counts) { + parsed[sectionName] = []; + for (let i = 0; i < count; ++i) { + const { nread, domain } = readDomainFromPacket(buffer, offset); + offset += nread; + + const type = buffer.readUInt16BE(offset); + + const rr = { + domain, + cls: buffer.readUInt16BE(offset + 2), + }; + offset += 4; + + for (const name in types) { + if (types[name] === type) + rr.type = name; + } + + if (sectionName !== 'questions') { + rr.ttl = buffer.readInt32BE(offset); + const dataLength = buffer.readUInt16BE(offset); + offset += 6; + + switch (type) { + case types.A: + assert.strictEqual(dataLength, 4); + rr.address = `${buffer[offset + 0]}.${buffer[offset + 1]}.` + + `${buffer[offset + 2]}.${buffer[offset + 3]}`; + break; + case types.AAAA: + assert.strictEqual(dataLength, 16); + rr.address = buffer.toString('hex', offset, offset + 16) + .replace(/(.{4}(?!$))/g, '$1:'); + break; + case types.TXT: + { + let position = offset; + rr.entries = []; + while (position < offset + dataLength) { + const txtLength = buffer[offset]; + rr.entries.push(buffer.toString('utf8', + position + 1, + position + 1 + txtLength)); + position += 1 + txtLength; + } + assert.strictEqual(position, offset + dataLength); + break; + } + case types.MX: + { + rr.priority = buffer.readInt16BE(buffer, offset); + offset += 2; + const { nread, domain } = readDomainFromPacket(buffer, offset); + rr.exchange = domain; + assert.strictEqual(nread, dataLength); + break; + } + case types.NS: + case types.CNAME: + case types.PTR: + { + const { nread, domain } = readDomainFromPacket(buffer, offset); + rr.value = domain; + assert.strictEqual(nread, dataLength); + break; + } + case types.SOA: + { + const mname = readDomainFromPacket(buffer, offset); + const rname = readDomainFromPacket(buffer, offset + mname.nread); + rr.nsname = mname.domain; + rr.hostmaster = rname.domain; + const trailerOffset = offset + mname.nread + rname.nread; + rr.serial = buffer.readUInt32BE(trailerOffset); + rr.refresh = buffer.readUInt32BE(trailerOffset + 4); + rr.retry = buffer.readUInt32BE(trailerOffset + 8); + rr.expire = buffer.readUInt32BE(trailerOffset + 12); + rr.minttl = buffer.readUInt32BE(trailerOffset + 16); + + assert.strictEqual(trailerOffset + 20, dataLength); + break; + } + default: + throw new Error(`Unknown RR type ${rr.type}`); + } + offset += dataLength; + } + + parsed[sectionName].push(rr); + + assert.ok(offset <= buffer.length); + } + } + + assert.strictEqual(offset, buffer.length); + return parsed; +} + +function writeIPv6(ip) { + const parts = ip.replace(/^:|:$/g, '').split(':'); + const buf = Buffer.alloc(16); + + let offset = 0; + for (const part of parts) { + if (part === '') { + offset += 16 - 2 * (parts.length - 1); + } else { + buf.writeUInt16BE(parseInt(part, 16), offset); + offset += 2; + } + } + + return buf; +} + +function writeDomainName(domain) { + return Buffer.concat(domain.split('.').map((label) => { + assert(label.length < 64); + return Buffer.concat([ + Buffer.from([label.length]), + Buffer.from(label, 'ascii') + ]); + }).concat([Buffer.alloc(1)])); +} + +function writeDNSPacket(parsed) { + const buffers = []; + const kStandardResponseFlags = 0x8180; + + buffers.push(new Uint16Array([ + parsed.id, + parsed.flags === undefined ? kStandardResponseFlags : parsed.flags, + parsed.questions && parsed.questions.length, + parsed.answers && parsed.answers.length, + parsed.authorityAnswers && parsed.authorityAnswers.length, + parsed.additionalRecords && parsed.additionalRecords.length, + ])); + + for (const q of parsed.questions) { + assert(types[q.type]); + buffers.push(writeDomainName(q.domain)); + buffers.push(new Uint16Array([ + types[q.type], + q.cls === undefined ? classes.IN : q.cls + ])); + } + + for (const rr of [].concat(parsed.answers, + parsed.authorityAnswers, + parsed.additionalRecords)) { + if (!rr) continue; + + assert(types[rr.type]); + buffers.push(writeDomainName(rr.domain)); + buffers.push(new Uint16Array([ + types[rr.type], + rr.cls === undefined ? classes.IN : rr.cls + ])); + buffers.push(new Int32Array([rr.ttl])); + + const rdLengthBuf = new Uint16Array(1); + buffers.push(rdLengthBuf); + + switch (rr.type) { + case 'A': + rdLengthBuf[0] = 4; + buffers.push(new Uint8Array(rr.address.split('.'))); + break; + case 'AAAA': + rdLengthBuf[0] = 16; + buffers.push(writeIPv6(rr.address)); + break; + case 'TXT': + const total = rr.entries.map((s) => s.length).reduce((a, b) => a + b); + // Total length of all strings + 1 byte each for their lengths. + rdLengthBuf[0] = rr.entries.length + total; + for (const txt of rr.entries) { + buffers.push(new Uint8Array([Buffer.byteLength(txt)])); + buffers.push(Buffer.from(txt)); + } + break; + case 'MX': + rdLengthBuf[0] = 2; + buffers.push(new Uint16Array([rr.priority])); + // fall through + case 'NS': + case 'CNAME': + case 'PTR': + { + const domain = writeDomainName(rr.exchange || rr.value); + rdLengthBuf[0] += domain.length; + buffers.push(domain); + break; + } + case 'SOA': + { + const mname = writeDomainName(rr.nsname); + const rname = writeDomainName(rr.hostmaster); + rdLengthBuf[0] = mname.length + rname.length + 20; + buffers.push(mname, rname); + buffers.push(new Uint32Array([ + rr.serial, rr.refresh, rr.retry, rr.expire, rr.minttl + ])); + break; + } + default: + throw new Error(`Unknown RR type ${rr.type}`); + } + } + + return Buffer.concat(buffers.map((typedArray) => { + const buf = Buffer.from(typedArray.buffer, + typedArray.byteOffset, + typedArray.byteLength); + if (os.endianness() === 'LE') { + if (typedArray.BYTES_PER_ELEMENT === 2) buf.swap16(); + if (typedArray.BYTES_PER_ELEMENT === 4) buf.swap32(); + } + return buf; + })); +} + +module.exports = { types, classes, writeDNSPacket, parseDNSPacket }; diff --git a/test/parallel/test-dns-resolveany-bad-ancount.js b/test/parallel/test-dns-resolveany-bad-ancount.js new file mode 100644 index 00000000000000..25ce15935caad9 --- /dev/null +++ b/test/parallel/test-dns-resolveany-bad-ancount.js @@ -0,0 +1,35 @@ +'use strict'; +const common = require('../common'); +const dnstools = require('../common/dns'); +const dns = require('dns'); +const assert = require('assert'); +const dgram = require('dgram'); + +const server = dgram.createSocket('udp4'); + +server.on('message', common.mustCall((msg, { address, port }) => { + const parsed = dnstools.parseDNSPacket(msg); + const domain = parsed.questions[0].domain; + assert.strictEqual(domain, 'example.org'); + + const buf = dnstools.writeDNSPacket({ + id: parsed.id, + questions: parsed.questions, + answers: { type: 'A', address: '1.2.3.4', ttl: 123, domain }, + }); + // Overwrite the # of answers with 2, which is incorrect. + buf.writeUInt16LE(2, 6); + server.send(buf, port, address); +})); + +server.bind(0, common.mustCall(() => { + const address = server.address(); + dns.setServers([`127.0.0.1:${address.port}`]); + + dns.resolveAny('example.org', common.mustCall((err) => { + assert.strictEqual(err.code, 'EBADRESP'); + assert.strictEqual(err.syscall, 'queryAny'); + assert.strictEqual(err.hostname, 'example.org'); + server.close(); + })); +})); diff --git a/test/parallel/test-dns-resolveany.js b/test/parallel/test-dns-resolveany.js new file mode 100644 index 00000000000000..7ad0d3b0fa38d9 --- /dev/null +++ b/test/parallel/test-dns-resolveany.js @@ -0,0 +1,53 @@ +'use strict'; +const common = require('../common'); +const dnstools = require('../common/dns'); +const dns = require('dns'); +const assert = require('assert'); +const dgram = require('dgram'); + +const answers = [ + { type: 'A', address: '1.2.3.4', ttl: 123 }, + { type: 'AAAA', address: '::42', ttl: 123 }, + { type: 'MX', priority: 42, exchange: 'foobar.com', ttl: 124 }, + { type: 'NS', value: 'foobar.org', ttl: 457 }, + { type: 'TXT', entries: [ 'v=spf1 ~all', 'xyz' ] }, + { type: 'PTR', value: 'baz.org', ttl: 987 }, + { + type: 'SOA', + nsname: 'ns1.example.com', + hostmaster: 'admin.example.com', + serial: 156696742, + refresh: 900, + retry: 900, + expire: 1800, + minttl: 60 + }, +]; + +const server = dgram.createSocket('udp4'); + +server.on('message', common.mustCall((msg, { address, port }) => { + const parsed = dnstools.parseDNSPacket(msg); + const domain = parsed.questions[0].domain; + assert.strictEqual(domain, 'example.org'); + + server.send(dnstools.writeDNSPacket({ + id: parsed.id, + questions: parsed.questions, + answers: answers.map((answer) => Object.assign({ domain }, answer)), + }), port, address); +})); + +server.bind(0, common.mustCall(() => { + const address = server.address(); + dns.setServers([`127.0.0.1:${address.port}`]); + + dns.resolveAny('example.org', common.mustCall((err, res) => { + assert.ifError(err); + // Compare copies with ttl removed, c-ares fiddles with that value. + assert.deepStrictEqual( + res.map((r) => Object.assign({}, r, { ttl: null })), + answers.map((r) => Object.assign({}, r, { ttl: null }))); + server.close(); + })); +}));