framed_encrypt_stream.test.ts

/*
 * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"). You may not use
 * this file except in compliance with the License. A copy of the License is
 * located at
 *
 *     http://aws.amazon.com/apache2.0/
 *
 * or in the "license" file accompanying this file. This file is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
 * implied. See the License for the specific language governing permissions and
 * limitations under the License.
 */

/* eslint-env mocha */

import * as chai from 'chai'
import chaiAsPromised from 'chai-as-promised'
import { getFramedEncryptStream, getEncryptFrame } from '../src/framed_encrypt_stream'

chai.use(chaiAsPromised)
const { expect } = chai

describe('getFramedEncryptStream', () => {
  it('can be created', () => {
    const getCipher: any = () => {}
    const test = getFramedEncryptStream(getCipher, {} as any, () => {})
    expect(test._transform).is.a('function')
  })

  it('Precondition: plaintextLength must be within bounds.', () => {
    const getCipher: any = () => {}
    expect(() => getFramedEncryptStream(getCipher, {} as any, () => {}, -1)).to.throw(Error, 'plaintextLength out of bounds.')
    expect(() => getFramedEncryptStream(getCipher, {} as any, () => {}, Number.MAX_SAFE_INTEGER + 1)).to.throw(Error, 'plaintextLength out of bounds.')

    /* Math is hard.
     * I want to make sure that I don't have an errant off by 1 error.
     */
    expect(() => getFramedEncryptStream(getCipher, {} as any, () => {}, Number.MAX_SAFE_INTEGER)).to.not.throw(Error)
  })

  it('Precondition: Must not process more than plaintextLength.', () => {
    const getCipher: any = () => {}
    const test = getFramedEncryptStream(getCipher, { } as any, () => {}, 8)

    expect(() => test._transform(Buffer.from(Array(9)), 'binary', () => {})).to.throw(Error, 'Encrypted data exceeded plaintextLength.')
  })

  it('Check for early return (Postcondition): Have not accumulated a frame.', () => {
    const getCipher: any = () => {}
    const frameLength = 10
    const test = getFramedEncryptStream(getCipher, { frameLength } as any, () => {})

    let called = false
    test._transform(Buffer.from(Array(9)), 'binary', () => {
      called = true
    })

    expect(called).to.equal(true)
  })
})

describe('getEncryptFrame', () => {
  it('can return an EncryptFrame', () => {
    const input = {
      pendingFrame: {
        content: [Buffer.from([1, 2, 3, 4, 5])],
        contentLength: 5,
        sequenceNumber: 1
      },
      isFinalFrame: false,
      getCipher: () => ({ setAAD: () => {} }) as any,
      messageHeader: {
        frameLength: 5,
        contentType: 2,
        messageId: Buffer.from([]),
        headerIvLength: 12 as 12,
        version: 1,
        type: 12,
        suiteId: 1,
        encryptionContext: {},
        encryptedDataKeys: []
      }
    }
    const test1 = getEncryptFrame(input)
    expect(test1.content).to.equal(input.pendingFrame.content)
    expect(test1.isFinalFrame).to.equal(input.isFinalFrame)

    // Just a quick flip to make sure...
    input.isFinalFrame = true
    const test2 = getEncryptFrame(input)
    expect(test2.content).to.equal(input.pendingFrame.content)
    expect(test2.isFinalFrame).to.equal(input.isFinalFrame)
  })

  it('Precondition: The content length MUST correlate with the frameLength.', () => {
    const inputFinalFrameToLarge = {
      pendingFrame: {
        content: [Buffer.from([1, 2, 3, 4, 5, 6])],
        // This exceeds the frameLength below
        contentLength: 6,
        sequenceNumber: 1
      },
      isFinalFrame: true,
      getCipher: () => ({ setAAD: () => {} }) as any,
      messageHeader: {
        frameLength: 5,
        contentType: 2,
        messageId: Buffer.from([]),
        headerIvLength: 12 as 12,
        version: 1,
        type: 12,
        suiteId: 1,
        encryptionContext: {},
        encryptedDataKeys: []
      }
    }

    expect(() => getEncryptFrame(inputFinalFrameToLarge)).to.throw('Malformed frame length and content length:')

    const inputFrame = {
      pendingFrame: {
        content: [Buffer.from([1, 2, 3, 4, 5])],
        contentLength: 5,
        sequenceNumber: 1
      },
      isFinalFrame: false,
      getCipher: () => ({ setAAD: () => {} }) as any,
      messageHeader: {
        frameLength: 5,
        contentType: 2,
        messageId: Buffer.from([]),
        headerIvLength: 12 as 12,
        version: 1,
        type: 12,
        suiteId: 1,
        encryptionContext: {},
        encryptedDataKeys: []
      }
    }

    // Make sure that it must be equal as long as we are here...
    inputFrame.pendingFrame.contentLength = 4
    expect(() => getEncryptFrame(inputFrame)).to.throw('Malformed frame length and content length:')
    inputFrame.pendingFrame.contentLength = 6
    expect(() => getEncryptFrame(inputFrame)).to.throw('Malformed frame length and content length:')
  })
})