botfights/server/src/middleware/nip98.test.ts

import { describe, it, expect, vi, afterEach } from 'vitest'
import { verifyNip98Token } from './nip98.js'
import { generateSecretKey, getPublicKey, finalizeEvent } from 'nostr-tools'

function createNip98Event(
  sk: Uint8Array,
  url: string,
  method: string,
  overrides: Record<string, unknown> = {},
) {
  const event = {
    kind: 27235,
    created_at: Math.floor(Date.now() / 1000),
    tags: [
      ['u', url],
      ['method', method],
    ],
    content: '',
    ...overrides,
  }
  return finalizeEvent(event, sk)
}

function toAuthHeader(event: object): string {
  return `Nostr ${Buffer.from(JSON.stringify(event)).toString('base64')}`
}

describe('verifyNip98Token', () => {
  afterEach(() => {
    vi.useRealTimers()
  })

  it('accepts a valid NIP-98 token', () => {
    const sk = generateSecretKey()
    const pk = getPublicKey(sk)
    const event = createNip98Event(sk, 'https://example.com/api/auth/nostr/session', 'POST')
    const header = toAuthHeader(event)

    const result = verifyNip98Token(header, '/api/auth/nostr/session', 'POST')
    expect(result.valid).toBe(true)
    expect(result.pubkey).toBe(pk)
  })

  it('rejects expired token (>120s)', () => {
    const sk = generateSecretKey()
    const event = createNip98Event(sk, 'https://example.com/api/auth', 'POST', {
      created_at: Math.floor(Date.now() / 1000) - 200,
    })
    // Need to re-finalize with the old created_at
    // Actually createNip98Event's overrides merge before finalize, but created_at gets set by finalizeEvent
    // Let me build manually
    const rawEvent = {
      kind: 27235,
      created_at: Math.floor(Date.now() / 1000) - 200,
      tags: [['u', 'https://example.com/api/auth'], ['method', 'POST']],
      content: '',
    }
    const signed = finalizeEvent(rawEvent, sk)
    const header = toAuthHeader(signed)

    const result = verifyNip98Token(header, '/api/auth', 'POST')
    expect(result.valid).toBe(false)
    expect(result.error).toContain('expired')
  })

  it('rejects wrong method', () => {
    const sk = generateSecretKey()
    const event = createNip98Event(sk, 'https://example.com/api/auth', 'POST')
    const header = toAuthHeader(event)

    const result = verifyNip98Token(header, '/api/auth', 'GET')
    expect(result.valid).toBe(false)
    expect(result.error).toContain('Method mismatch')
  })

  it('rejects invalid signature (tampered event)', () => {
    const sk = generateSecretKey()
    const event = createNip98Event(sk, 'https://example.com/api/auth', 'POST')
    // Tamper with pubkey
    const tampered = { ...event, pubkey: '0'.repeat(64) }
    const header = toAuthHeader(tampered)

    const result = verifyNip98Token(header, '/api/auth', 'POST')
    expect(result.valid).toBe(false)
    expect(result.error).toContain('Invalid signature')
  })

  it('rejects missing URL tag', () => {
    const sk = generateSecretKey()
    const event = finalizeEvent({
      kind: 27235,
      created_at: Math.floor(Date.now() / 1000),
      tags: [['method', 'POST']],
      content: '',
    }, sk)
    const header = toAuthHeader(event)

    const result = verifyNip98Token(header, '/api/auth', 'POST')
    expect(result.valid).toBe(false)
    expect(result.error).toContain('Missing URL tag')
  })

  it('rejects invalid auth header format', () => {
    const result = verifyNip98Token('Bearer xyz123', '/api/auth', 'POST')
    expect(result.valid).toBe(false)
    expect(result.error).toContain('Invalid auth header format')
  })

  it('rejects wrong event kind', () => {
    const sk = generateSecretKey()
    const event = finalizeEvent({
      kind: 1, // Regular note, not 27235
      created_at: Math.floor(Date.now() / 1000),
      tags: [['u', 'https://example.com/api/auth'], ['method', 'POST']],
      content: '',
    }, sk)
    const header = toAuthHeader(event)

    const result = verifyNip98Token(header, '/api/auth', 'POST')
    expect(result.valid).toBe(false)
    expect(result.error).toContain('Wrong event kind')
  })

  it('token replay: same valid token accepted twice within 120s (no replay protection)', () => {
    // FINDING: NIP-98 spec doesn't mandate replay protection.
    // The server verifies signature and timestamp but does not track seen event IDs.
    // A valid token can be replayed within its 120s window.
    // Mitigation: JWT is issued on first use, so replay only re-issues JWT for same pubkey.
    const sk = generateSecretKey()
    const event = createNip98Event(sk, 'https://example.com/api/auth', 'POST')
    const header = toAuthHeader(event)

    const result1 = verifyNip98Token(header, '/api/auth', 'POST')
    const result2 = verifyNip98Token(header, '/api/auth', 'POST')
    expect(result1.valid).toBe(true)
    expect(result2.valid).toBe(true) // No replay protection — documenting behavior
  })

  it('rejects clock drift >120s in the future', () => {
    const sk = generateSecretKey()
    const event = finalizeEvent({
      kind: 27235,
      created_at: Math.floor(Date.now() / 1000) + 200, // 200s in the future
      tags: [['u', 'https://example.com/api/auth'], ['method', 'POST']],
      content: '',
    }, sk)
    const header = toAuthHeader(event)

    const result = verifyNip98Token(header, '/api/auth', 'POST')
    expect(result.valid).toBe(false)
    expect(result.error).toContain('expired')
  })

  it('rejects URL path mismatch', () => {
    const sk = generateSecretKey()
    const event = createNip98Event(sk, 'https://example.com/api/auth/login', 'POST')
    const header = toAuthHeader(event)

    const result = verifyNip98Token(header, '/api/auth/session', 'POST')
    expect(result.valid).toBe(false)
    expect(result.error).toContain('URL path mismatch')
  })
})