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Security: Prevent OAuth CSRF, open redirect, and account takeover #2

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112 changes: 69 additions & 43 deletions Realism/app/api/connectors/spotify/auth/route.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,43 +1,69 @@
import { NextRequest, NextResponse } from 'next/server'
import { validateSession } from '@/lib/auth'

export async function GET(req: NextRequest) {
const token = req.cookies.get('realism-session')?.value
if (!token) {
return NextResponse.redirect(new URL('/?auth=required', req.url))
}

const userId = await validateSession(token)
if (!userId) {
return NextResponse.redirect(new URL('/?auth=required', req.url))
}

const clientId = process.env.SPOTIFY_CLIENT_ID
if (!clientId) {
return NextResponse.json(
{ error: 'Spotify is not configured on this server' },
{ status: 503 }
)
}

const returnTo = req.nextUrl.searchParams.get('returnTo') ?? '/dashboard'
const state = Buffer.from(`${userId}:${returnTo}`).toString('base64url')

const scopes = [
'user-top-read',
'user-read-recently-played',
'user-read-private',
].join(' ')

const params = new URLSearchParams({
client_id: clientId,
response_type: 'code',
redirect_uri: `${process.env.NEXT_PUBLIC_APP_URL}/api/connectors/spotify/callback`,
scope: scopes,
state,
})

return NextResponse.redirect(
`https://accounts.spotify.com/authorize?${params}`
)
}
import { NextRequest, NextResponse } from 'next/server'
import { validateSession } from '@/lib/auth'

export async function GET(req: NextRequest) {
const token = req.cookies.get('realism-session')?.value
if (!token) {
return NextResponse.redirect(new URL('/?auth=required', req.url))
}

const userId = await validateSession(token)
if (!userId) {
return NextResponse.redirect(new URL('/?auth=required', req.url))
}

const clientId = process.env.SPOTIFY_CLIENT_ID
if (!clientId) {
return NextResponse.json(
{ error: 'Spotify is not configured on this server' },
{ status: 503 }
)
}

let returnTo = req.nextUrl.searchParams.get('returnTo') ?? '/dashboard'

// SECURITY FIX: Open Redirect Prevention.
// Ensure the returnTo path is strictly a relative local path.
// Reject absolute URLs or protocol-relative URLs (//evil.com).
if (!returnTo.startsWith('/') || returnTo.startsWith('//')) {
returnTo = '/dashboard'
}

// SECURITY FIX: CSRF Prevention.
// Generate a random nonce to securely bind the OAuth flow to the current browser session.
// We no longer expose the userId in the unsigned state parameter to prevent spoofing.
const nonce = crypto.randomUUID()
const statePayload = JSON.stringify({ returnTo, nonce })
const state = Buffer.from(statePayload).toString('base64url')

const scopes = [
'user-top-read',
'user-read-recently-played',
'user-read-private',
].join(' ')

const params = new URLSearchParams({
client_id: clientId,
response_type: 'code',
redirect_uri: `${process.env.NEXT_PUBLIC_APP_URL}/api/connectors/spotify/callback`,
scope: scopes,
state,
})

const response = NextResponse.redirect(
`https://accounts.spotify.com/authorize?${params}`
)

// SECURITY FIX: Set the nonce in a short-lived, HTTP-only, secure cookie.
response.cookies.set({
name: 'spotify-oauth-nonce',
value: nonce,
httpOnly: true,
secure: process.env.NODE_ENV === 'production',
sameSite: 'lax',
path: '/',
maxAge: 600, // Valid for 10 minutes
})

return response
}
224 changes: 127 additions & 97 deletions Realism/app/api/connectors/spotify/callback/route.ts
View file
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Original file line number Diff line number Diff line change
@@ -1,97 +1,127 @@
import { NextRequest, NextResponse } from 'next/server'
import { setConnectorCredentials } from '@/lib/live-apps'

export async function GET(req: NextRequest) {
const { searchParams } = req.nextUrl
const code = searchParams.get('code')
const state = searchParams.get('state')
const error = searchParams.get('error')

if (error) {
return NextResponse.redirect(
new URL('/dashboard?connector_error=spotify_denied', req.url)
)
}

if (!code || !state) {
return NextResponse.redirect(
new URL('/dashboard?connector_error=spotify_invalid', req.url)
)
}

let userId: string
let returnTo: string
try {
const decoded = Buffer.from(state, 'base64url').toString()
const colonIndex = decoded.indexOf(':')
userId = decoded.slice(0, colonIndex)
returnTo = decoded.slice(colonIndex + 1) || '/dashboard'
} catch {
return NextResponse.redirect(
new URL('/dashboard?connector_error=spotify_state', req.url)
)
}

if (!userId) {
return NextResponse.redirect(
new URL('/dashboard?connector_error=spotify_state', req.url)
)
}

const clientId = process.env.SPOTIFY_CLIENT_ID
const clientSecret = process.env.SPOTIFY_CLIENT_SECRET

if (!clientId || !clientSecret) {
return NextResponse.redirect(
new URL('/dashboard?connector_error=spotify_config', req.url)
)
}

let tokenData: {
access_token: string
refresh_token: string
expires_in: number
token_type: string
}

try {
const tokenRes = await fetch('https://accounts.spotify.com/api/token', {
method: 'POST',
headers: {
'Content-Type': 'application/x-www-form-urlencoded',
'Authorization': `Basic ${Buffer.from(`${clientId}:${clientSecret}`).toString('base64')}`,
},
body: new URLSearchParams({
grant_type: 'authorization_code',
code,
redirect_uri: `${process.env.NEXT_PUBLIC_APP_URL}/api/connectors/spotify/callback`,
}),
})

if (!tokenRes.ok) {
const errText = await tokenRes.text()
console.error('[spotify/callback] Token exchange failed:', errText)
return NextResponse.redirect(
new URL('/dashboard?connector_error=spotify_token', req.url)
)
}

tokenData = await tokenRes.json()
} catch (err) {
console.error('[spotify/callback] Token exchange error:', err)
return NextResponse.redirect(
new URL('/dashboard?connector_error=spotify_token', req.url)
)
}

await setConnectorCredentials(userId, 'spotify', {
accessToken: tokenData.access_token,
refreshToken: tokenData.refresh_token,
expiresAt: new Date(Date.now() + tokenData.expires_in * 1000).toISOString(),
})

const redirectUrl = new URL(returnTo, req.url)
redirectUrl.searchParams.set('connector_connected', 'spotify')

return NextResponse.redirect(redirectUrl)
}
import { NextRequest, NextResponse } from 'next/server'
import { setConnectorCredentials } from '@/lib/live-apps'
import { validateSession } from '@/lib/auth'

export async function GET(req: NextRequest) {
const { searchParams } = req.nextUrl
const code = searchParams.get('code')
const state = searchParams.get('state')
const error = searchParams.get('error')

if (error) {
return NextResponse.redirect(
new URL('/dashboard?connector_error=spotify_denied', req.url)
)
}

if (!code || !state) {
return NextResponse.redirect(
new URL('/dashboard?connector_error=spotify_invalid', req.url)
)
}

// SECURITY FIX: Account Takeover & Identity Confusion Prevention.
// We do NOT trust the userId from the OAuth state parameter.
// Instead, we strictly re-validate the current user's session to ensure
// the credentials are bound to the genuinely authenticated user.
const sessionToken = req.cookies.get('realism-session')?.value
if (!sessionToken) {
return NextResponse.redirect(new URL('/?auth=required', req.url))
}

const userId = await validateSession(sessionToken)
if (!userId) {
return NextResponse.redirect(new URL('/?auth=required', req.url))
}

let returnTo = '/dashboard'
let nonce = ''

try {
const decoded = Buffer.from(state, 'base64url').toString()
const payload = JSON.parse(decoded)
returnTo = payload.returnTo || '/dashboard'
nonce = payload.nonce || ''
} catch {
return NextResponse.redirect(
new URL('/dashboard?connector_error=spotify_state', req.url)
)
}

// SECURITY FIX: CSRF Prevention.
// Verify that the nonce in the state payload strictly matches the nonce cookie.
const cookieNonce = req.cookies.get('spotify-oauth-nonce')?.value
if (!cookieNonce || nonce !== cookieNonce) {
return NextResponse.redirect(
new URL('/dashboard?connector_error=spotify_state_mismatch', req.url)
)
}

// SECURITY FIX: Open Redirect Prevention.
// Ensure the decoded returnTo path is strictly a relative local path.
if (!returnTo.startsWith('/') || returnTo.startsWith('//')) {
returnTo = '/dashboard'
}

const clientId = process.env.SPOTIFY_CLIENT_ID
const clientSecret = process.env.SPOTIFY_CLIENT_SECRET

if (!clientId || !clientSecret) {
return NextResponse.redirect(
new URL('/dashboard?connector_error=spotify_config', req.url)
)
}

let tokenData: {
access_token: string
refresh_token: string
expires_in: number
token_type: string
}

try {
const tokenRes = await fetch('https://accounts.spotify.com/api/token', {
method: 'POST',
headers: {
'Content-Type': 'application/x-www-form-urlencoded',
'Authorization': `Basic ${Buffer.from(`${clientId}:${clientSecret}`).toString('base64')}`,
},
body: new URLSearchParams({
grant_type: 'authorization_code',
code,
redirect_uri: `${process.env.NEXT_PUBLIC_APP_URL}/api/connectors/spotify/callback`,
}),
})

if (!tokenRes.ok) {
const errText = await tokenRes.text()
console.error('[spotify/callback] Token exchange failed:', errText)
return NextResponse.redirect(
new URL('/dashboard?connector_error=spotify_token', req.url)
)
}

tokenData = await tokenRes.json()
} catch (err) {
console.error('[spotify/callback] Token exchange error:', err)
return NextResponse.redirect(
new URL('/dashboard?connector_error=spotify_token', req.url)
)
}

await setConnectorCredentials(userId, 'spotify', {
accessToken: tokenData.access_token,
refreshToken: tokenData.refresh_token,
expiresAt: new Date(Date.now() + tokenData.expires_in * 1000).toISOString(),
})

const redirectUrl = new URL(returnTo, req.url)
redirectUrl.searchParams.set('connector_connected', 'spotify')

const response = NextResponse.redirect(redirectUrl)

// SECURITY FIX: Clean up the nonce cookie after successful authentication to prevent reuse.
response.cookies.delete('spotify-oauth-nonce')

return response
}