init source

node_modules/pg/lib/sasl.js

@@ -0,0 +1,147 @@
+'use strict'
+const crypto = require('crypto')
+
+function startSession (mechanisms) {
+  if (mechanisms.indexOf('SCRAM-SHA-256') === -1) {
+    throw new Error('SASL: Only mechanism SCRAM-SHA-256 is currently supported')
+  }
+
+  const clientNonce = crypto.randomBytes(18).toString('base64')
+
+  return {
+    mechanism: 'SCRAM-SHA-256',
+    clientNonce,
+    response: 'n,,n=*,r=' + clientNonce,
+    message: 'SASLInitialResponse'
+  }
+}
+
+function continueSession (session, password, serverData) {
+  if (session.message !== 'SASLInitialResponse') {
+    throw new Error('SASL: Last message was not SASLInitialResponse')
+  }
+
+  const sv = extractVariablesFromFirstServerMessage(serverData)
+
+  if (!sv.nonce.startsWith(session.clientNonce)) {
+    throw new Error('SASL: SCRAM-SERVER-FIRST-MESSAGE: server nonce does not start with client nonce')
+  }
+
+  var saltBytes = Buffer.from(sv.salt, 'base64')
+
+  var saltedPassword = Hi(password, saltBytes, sv.iteration)
+
+  var clientKey = createHMAC(saltedPassword, 'Client Key')
+  var storedKey = crypto.createHash('sha256').update(clientKey).digest()
+
+  var clientFirstMessageBare = 'n=*,r=' + session.clientNonce
+  var serverFirstMessage = 'r=' + sv.nonce + ',s=' + sv.salt + ',i=' + sv.iteration
+
+  var clientFinalMessageWithoutProof = 'c=biws,r=' + sv.nonce
+
+  var authMessage = clientFirstMessageBare + ',' + serverFirstMessage + ',' + clientFinalMessageWithoutProof
+
+  var clientSignature = createHMAC(storedKey, authMessage)
+  var clientProofBytes = xorBuffers(clientKey, clientSignature)
+  var clientProof = clientProofBytes.toString('base64')
+
+  var serverKey = createHMAC(saltedPassword, 'Server Key')
+  var serverSignatureBytes = createHMAC(serverKey, authMessage)
+
+  session.message = 'SASLResponse'
+  session.serverSignature = serverSignatureBytes.toString('base64')
+  session.response = clientFinalMessageWithoutProof + ',p=' + clientProof
+}
+
+function finalizeSession (session, serverData) {
+  if (session.message !== 'SASLResponse') {
+    throw new Error('SASL: Last message was not SASLResponse')
+  }
+
+  var serverSignature
+
+  String(serverData).split(',').forEach(function (part) {
+    switch (part[0]) {
+      case 'v':
+        serverSignature = part.substr(2)
+        break
+    }
+  })
+
+  if (serverSignature !== session.serverSignature) {
+    throw new Error('SASL: SCRAM-SERVER-FINAL-MESSAGE: server signature does not match')
+  }
+}
+
+function extractVariablesFromFirstServerMessage (data) {
+  var nonce, salt, iteration
+
+  String(data).split(',').forEach(function (part) {
+    switch (part[0]) {
+      case 'r':
+        nonce = part.substr(2)
+        break
+      case 's':
+        salt = part.substr(2)
+        break
+      case 'i':
+        iteration = parseInt(part.substr(2), 10)
+        break
+    }
+  })
+
+  if (!nonce) {
+    throw new Error('SASL: SCRAM-SERVER-FIRST-MESSAGE: nonce missing')
+  }
+
+  if (!salt) {
+    throw new Error('SASL: SCRAM-SERVER-FIRST-MESSAGE: salt missing')
+  }
+
+  if (!iteration) {
+    throw new Error('SASL: SCRAM-SERVER-FIRST-MESSAGE: iteration missing')
+  }
+
+  return {
+    nonce,
+    salt,
+    iteration
+  }
+}
+
+function xorBuffers (a, b) {
+  if (!Buffer.isBuffer(a)) a = Buffer.from(a)
+  if (!Buffer.isBuffer(b)) b = Buffer.from(b)
+  var res = []
+  if (a.length > b.length) {
+    for (var i = 0; i < b.length; i++) {
+      res.push(a[i] ^ b[i])
+    }
+  } else {
+    for (var j = 0; j < a.length; j++) {
+      res.push(a[j] ^ b[j])
+    }
+  }
+  return Buffer.from(res)
+}
+
+function createHMAC (key, msg) {
+  return crypto.createHmac('sha256', key).update(msg).digest()
+}
+
+function Hi (password, saltBytes, iterations) {
+  var ui1 = createHMAC(password, Buffer.concat([saltBytes, Buffer.from([0, 0, 0, 1])]))
+  var ui = ui1
+  for (var i = 0; i < iterations - 1; i++) {
+    ui1 = createHMAC(password, ui1)
+    ui = xorBuffers(ui, ui1)
+  }
+
+  return ui
+}
+
+module.exports = {
+  startSession,
+  continueSession,
+  finalizeSession
+}