How to use express.js and passport.js with G Suite SAML Apps SSO

app.js

const express = require('express')
const SamlStrategy = require('passport-saml').Strategy
const passport = require('passport')

const cookieSession = require('cookie-session')
const cookieParser = require('cookie-parser')

// Create express instance
const app = express()

// Configure your cookie session or alternatives
app.use(cookieParser())
app.use(cookieSession({
  name: 'session',
  keys: ['super secret'],
  maxAge: 2 * 24 * 60 * 60 * 1000 // 2 days
}))

app.use(passport.initialize())
app.use(passport.session())

passport.use(new SamlStrategy({
    protocol: 'https://',
    entryPoint: 'https://accounts.google.com/o/saml2/idp?idpid=', // SSO URL (Step 2)
    issuer: 'https://.../sp', // Entity ID (Step 4)
    path: '/auth/saml/callback', // ACS URL path (Step 4)
    cert: "MIICizCCAfQCCQCY8tKaMc0BMjANBgkqh ... W==", // Certificate without begin and end
  }, function (profile, done) {
    // Parse user profile data
    done(null, {
      email: profile.email,
      name: profile.name
    })
  })
)

passport.serializeUser(function (user, done) {
  done(null, user)
})

passport.deserializeUser(function (user, done) {
  done(null, user)
})

app.get('/login', passport.authenticate('saml', {
  successRedirect: '/',
  failureRedirect: '/login'
}))

app.get('/logout', function (req, res) {
  req.logout()
  res.end('You have logged out.')
})

app.post('/auth/saml/callback', passport.authenticate('saml', {
  failureRedirect: '/error',
  failureFlash: true
}), function (req, res) {
  res.redirect('/')
})

// Securing every path in production.
app.all('*', function (req, res, next) {
  if (req.isAuthenticated() || process.env.NODE_ENV !== 'production') {
    next()
  } else {
    res.redirect('/login')
  }
})

init.sh

# https://github.com/bergie/passport-saml
yarn add passport passport-saml

at the time of writing this comment this gist provided following example configuration:

...
passport.use(new SamlStrategy({
    protocol: 'https://',
    entryPoint: 'https://accounts.google.com/o/saml2/idp?idpid=', // SSO URL (Step 2)
    issuer: 'https://.../sp', // Entity ID (Step 4)
    path: '/auth/saml/callback' // ACS URL path (Step 4)

  }, function (profile, done) {
...

That configuration example does not provide cert option. Lack of cert means that if you are/were using passport-saml version < 3.0.0 verification of authn response digital signature is/was silenty skipped. I.e. attacker can impersonate anyone he/she chooses just by posting whatever authn response he/she wants to callback and passport-saml would consume it as if it would be perfectly valid response from IdP. This is remotely exploitable situation.

For additional information see:

1. node-saml/passport-saml#523
2. node-saml/passport-saml#180
3. node-saml/passport-saml#199

@fuxingloh @gabrielmoncea @Hugofromfrance

Hi,
I have changed all the required details and trying to login but the page redirect me to google login page again and again. In another browser its forwarding the request and loading infinitely. Please help me to solve the issue.