signal-desktop/ts/test-electron/Crypto_test.ts

1085 lines
34 KiB
TypeScript

// Copyright 2015 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only
import { assert } from 'chai';
import { readFileSync, unlinkSync, writeFileSync } from 'fs';
import { join } from 'path';
import { createCipheriv } from 'crypto';
import * as log from '../logging/log';
import * as Bytes from '../Bytes';
import * as Curve from '../Curve';
import {
PaddedLengths,
encryptProfileItemWithPadding,
decryptProfileName,
encryptProfile,
decryptProfile,
getRandomBytes,
constantTimeEqual,
generateRegistrationId,
deriveSecrets,
encryptDeviceName,
decryptDeviceName,
deriveAccessKey,
getAccessKeyVerifier,
verifyAccessKey,
deriveMasterKeyFromGroupV1,
encryptSymmetric,
decryptSymmetric,
sha256,
hmacSha256,
verifyHmacSha256,
randomInt,
encryptAttachment,
decryptAttachmentV1,
padAndEncryptAttachment,
CipherType,
} from '../Crypto';
import {
type HardcodedIVForEncryptionType,
_generateAttachmentIv,
decryptAttachmentV2,
encryptAttachmentV2ToDisk,
getAesCbcCiphertextLength,
getAttachmentCiphertextLength,
splitKeys,
generateAttachmentKeys,
} from '../AttachmentCrypto';
import { createTempDir, deleteTempDir } from '../updater/common';
import { uuidToBytes, bytesToUuid } from '../util/uuidToBytes';
const GHOST_KITTY_HASH =
'7bc77f27d92d00b4a1d57c480ca86dacc43d57bc318339c92119d1fbf6b557a5';
describe('Crypto', () => {
describe('encrypting and decrypting profile data', () => {
const NAME_PADDED_LENGTH = 53;
describe('encrypting and decrypting profile names', () => {
it('pads, encrypts, decrypts, and unpads a short string', () => {
const name = 'Alice';
const buffer = Bytes.fromString(name);
const key = getRandomBytes(32);
const encrypted = encryptProfileItemWithPadding(
buffer,
key,
PaddedLengths.Name
);
assert.equal(encrypted.byteLength, NAME_PADDED_LENGTH + 16 + 12);
const { given, family } = decryptProfileName(
Bytes.toBase64(encrypted),
key
);
assert.strictEqual(family, null);
assert.strictEqual(Bytes.toString(given), name);
});
it('handles a given name of the max, 53 characters', () => {
const name = '01234567890123456789012345678901234567890123456789123';
const buffer = Bytes.fromString(name);
const key = getRandomBytes(32);
const encrypted = encryptProfileItemWithPadding(
buffer,
key,
PaddedLengths.Name
);
assert.equal(encrypted.byteLength, NAME_PADDED_LENGTH + 16 + 12);
const { given, family } = decryptProfileName(
Bytes.toBase64(encrypted),
key
);
assert.strictEqual(Bytes.toString(given), name);
assert.strictEqual(family, null);
});
it('handles family/given name of the max, 53 characters', () => {
const name =
'01234567890123456789\u000001234567890123456789012345678912';
const buffer = Bytes.fromString(name);
const key = getRandomBytes(32);
const encrypted = encryptProfileItemWithPadding(
buffer,
key,
PaddedLengths.Name
);
assert.equal(encrypted.byteLength, NAME_PADDED_LENGTH + 16 + 12);
const { given, family } = decryptProfileName(
Bytes.toBase64(encrypted),
key
);
assert.strictEqual(Bytes.toString(given), '01234567890123456789');
assert.strictEqual(
family && Bytes.toString(family),
'01234567890123456789012345678912'
);
});
it('handles a string with family/given name', () => {
const name = 'Alice\0Jones';
const buffer = Bytes.fromString(name);
const key = getRandomBytes(32);
const encrypted = encryptProfileItemWithPadding(
buffer,
key,
PaddedLengths.Name
);
assert.equal(encrypted.byteLength, NAME_PADDED_LENGTH + 16 + 12);
const { given, family } = decryptProfileName(
Bytes.toBase64(encrypted),
key
);
assert.strictEqual(Bytes.toString(given), 'Alice');
assert.strictEqual(family && Bytes.toString(family), 'Jones');
});
it('works for empty string', () => {
const name = Bytes.fromString('');
const key = getRandomBytes(32);
const encrypted = encryptProfileItemWithPadding(
name,
key,
PaddedLengths.Name
);
assert.equal(encrypted.byteLength, NAME_PADDED_LENGTH + 16 + 12);
const { given, family } = decryptProfileName(
Bytes.toBase64(encrypted),
key
);
assert.strictEqual(family, null);
assert.strictEqual(given.byteLength, 0);
assert.strictEqual(Bytes.toString(given), '');
});
});
describe('encrypting and decrypting profile avatars', () => {
it('encrypts and decrypts', async () => {
const buffer = Bytes.fromString('This is an avatar');
const key = getRandomBytes(32);
const encrypted = encryptProfile(buffer, key);
assert(encrypted.byteLength === buffer.byteLength + 16 + 12);
const decrypted = decryptProfile(encrypted, key);
assert(constantTimeEqual(buffer, decrypted));
});
it('throws when decrypting with the wrong key', () => {
const buffer = Bytes.fromString('This is an avatar');
const key = getRandomBytes(32);
const badKey = getRandomBytes(32);
const encrypted = encryptProfile(buffer, key);
assert(encrypted.byteLength === buffer.byteLength + 16 + 12);
assert.throws(
() => decryptProfile(encrypted, badKey),
'Failed to decrypt profile data. Most likely the profile key has changed.'
);
});
});
});
describe('generateRegistrationId', () => {
it('generates an integer between 1 and 16383 (inclusive)', () => {
let max = -1;
for (let i = 0; i < 100; i += 1) {
const id = generateRegistrationId();
assert.isAtLeast(id, 1);
assert.isAtMost(id, 16383);
assert(Number.isInteger(id));
max = Math.max(max, id);
}
// Probability of this being false is ~ 10^{-181}
assert.isAtLeast(max, 0x100);
});
});
describe('deriveSecrets', () => {
it('derives key parts via HKDF', () => {
const input = getRandomBytes(32);
const salt = getRandomBytes(32);
const info = Bytes.fromString('Hello world');
const result = deriveSecrets(input, salt, info);
assert.lengthOf(result, 3);
result.forEach(part => {
// This is a smoke test; HKDF is tested as part of @signalapp/libsignal-client.
assert.instanceOf(part, Uint8Array);
assert.strictEqual(part.byteLength, 32);
});
});
});
describe('accessKey/profileKey', () => {
it('verification roundtrips', () => {
const profileKey = getRandomBytes(32);
const accessKey = deriveAccessKey(profileKey);
const verifier = getAccessKeyVerifier(accessKey);
const correct = verifyAccessKey(accessKey, verifier);
assert.strictEqual(correct, true);
});
});
describe('deriveMasterKeyFromGroupV1', () => {
const vectors = [
{
gv1: '00000000000000000000000000000000',
masterKey:
'dbde68f4ee9169081f8814eabc65523fea1359235c8cfca32b69e31dce58b039',
},
{
gv1: '000102030405060708090a0b0c0d0e0f',
masterKey:
'70884f78f07a94480ee36b67a4b5e975e92e4a774561e3df84c9076e3be4b9bf',
},
{
gv1: '7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f',
masterKey:
'e69bf7c183b288b4ea5745b7c52b651a61e57769fafde683a6fdf1240f1905f2',
},
{
gv1: 'ffffffffffffffffffffffffffffffff',
masterKey:
'dd3a7de23d10f18b64457fbeedc76226c112a730e4b76112e62c36c4432eb37d',
},
];
vectors.forEach((vector, index) => {
it(`vector ${index}`, () => {
const gv1 = Bytes.fromHex(vector.gv1);
const expectedHex = vector.masterKey;
const actual = deriveMasterKeyFromGroupV1(gv1);
const actualHex = Bytes.toHex(actual);
assert.strictEqual(actualHex, expectedHex);
});
});
});
describe('symmetric encryption', () => {
it('roundtrips', () => {
const message = 'this is my message';
const plaintext = Bytes.fromString(message);
const key = getRandomBytes(32);
const encrypted = encryptSymmetric(key, plaintext);
const decrypted = decryptSymmetric(key, encrypted);
const equal = constantTimeEqual(plaintext, decrypted);
if (!equal) {
throw new Error('The output and input did not match!');
}
});
it('roundtrip fails if nonce is modified', () => {
const message = 'this is my message';
const plaintext = Bytes.fromString(message);
const key = getRandomBytes(32);
const encrypted = encryptSymmetric(key, plaintext);
encrypted[2] += 2;
try {
decryptSymmetric(key, encrypted);
} catch (error) {
assert.strictEqual(
error.message,
'decryptSymmetric: Failed to decrypt; MAC verification failed'
);
return;
}
throw new Error('Expected error to be thrown');
});
it('roundtrip fails if mac is modified', () => {
const message = 'this is my message';
const plaintext = Bytes.fromString(message);
const key = getRandomBytes(32);
const encrypted = encryptSymmetric(key, plaintext);
encrypted[encrypted.length - 3] += 2;
try {
decryptSymmetric(key, encrypted);
} catch (error) {
assert.strictEqual(
error.message,
'decryptSymmetric: Failed to decrypt; MAC verification failed'
);
return;
}
throw new Error('Expected error to be thrown');
});
it('roundtrip fails if encrypted contents are modified', () => {
const message = 'this is my message';
const plaintext = Bytes.fromString(message);
const key = getRandomBytes(32);
const encrypted = encryptSymmetric(key, plaintext);
encrypted[35] += 9;
try {
decryptSymmetric(key, encrypted);
} catch (error) {
assert.strictEqual(
error.message,
'decryptSymmetric: Failed to decrypt; MAC verification failed'
);
return;
}
throw new Error('Expected error to be thrown');
});
});
describe('encrypted device name', () => {
it('roundtrips', () => {
const deviceName = 'v1.19.0 on Windows 10';
const identityKey = Curve.generateKeyPair();
const encrypted = encryptDeviceName(deviceName, identityKey.pubKey);
const decrypted = decryptDeviceName(encrypted, identityKey.privKey);
assert.strictEqual(decrypted, deviceName);
});
it('fails if iv is changed', () => {
const deviceName = 'v1.19.0 on Windows 10';
const identityKey = Curve.generateKeyPair();
const encrypted = encryptDeviceName(deviceName, identityKey.pubKey);
encrypted.syntheticIv = getRandomBytes(16);
try {
decryptDeviceName(encrypted, identityKey.privKey);
} catch (error) {
assert.strictEqual(
error.message,
'decryptDeviceName: synthetic IV did not match'
);
}
});
});
describe('verifyHmacSha256', () => {
it('rejects if their MAC is too short', () => {
const key = getRandomBytes(32);
const plaintext = Bytes.fromString('Hello world');
const ourMac = hmacSha256(key, plaintext);
const theirMac = ourMac.slice(0, -1);
let error;
try {
verifyHmacSha256(plaintext, key, theirMac, ourMac.byteLength);
} catch (err) {
error = err;
}
assert.instanceOf(error, Error);
assert.strictEqual(error.message, 'Bad MAC length');
});
it('rejects if their MAC is too long', () => {
const key = getRandomBytes(32);
const plaintext = Bytes.fromString('Hello world');
const ourMac = hmacSha256(key, plaintext);
const theirMac = Bytes.concatenate([ourMac, new Uint8Array([0xff])]);
let error;
try {
verifyHmacSha256(plaintext, key, theirMac, ourMac.byteLength);
} catch (err) {
error = err;
}
assert.instanceOf(error, Error);
assert.strictEqual(error.message, 'Bad MAC length');
});
it('rejects if our MAC is shorter than the specified length', () => {
const key = getRandomBytes(32);
const plaintext = Bytes.fromString('Hello world');
const ourMac = hmacSha256(key, plaintext);
const theirMac = ourMac;
let error;
try {
verifyHmacSha256(plaintext, key, theirMac, ourMac.byteLength + 1);
} catch (err) {
error = err;
}
assert.instanceOf(error, Error);
assert.strictEqual(error.message, 'Bad MAC length');
});
it("rejects if the MACs don't match", () => {
const plaintext = Bytes.fromString('Hello world');
const ourKey = getRandomBytes(32);
const ourMac = hmacSha256(ourKey, plaintext);
const theirKey = getRandomBytes(32);
const theirMac = hmacSha256(theirKey, plaintext);
let error;
try {
verifyHmacSha256(plaintext, ourKey, theirMac, ourMac.byteLength);
} catch (err) {
error = err;
}
assert.instanceOf(error, Error);
assert.strictEqual(error.message, 'Bad MAC');
});
it('resolves with undefined if the MACs match exactly', () => {
const key = getRandomBytes(32);
const plaintext = Bytes.fromString('Hello world');
const theirMac = hmacSha256(key, plaintext);
const result = verifyHmacSha256(
plaintext,
key,
theirMac,
theirMac.byteLength
);
assert.isUndefined(result);
});
it('resolves with undefined if the first `length` bytes of the MACs match', () => {
const key = getRandomBytes(32);
const plaintext = Bytes.fromString('Hello world');
const theirMac = hmacSha256(key, plaintext).slice(0, -5);
const result = verifyHmacSha256(
plaintext,
key,
theirMac,
theirMac.byteLength
);
assert.isUndefined(result);
});
});
describe('randomInt', () => {
it('returns random integers in a range (inclusive)', () => {
const seen = new Set<number>();
for (let i = 0; i < 1_000_000 || seen.size < 3; i += 1) {
seen.add(randomInt(1, 3));
}
assert.deepStrictEqual(seen, new Set([1, 2, 3]));
});
});
describe('uuidToBytes', () => {
it('converts valid UUIDs to Uint8Arrays', () => {
const expectedResult = new Uint8Array([
0x22, 0x6e, 0x44, 0x02, 0x7f, 0xfc, 0x45, 0x43, 0x85, 0xc9, 0x46, 0x22,
0xc5, 0x0a, 0x5b, 0x14,
]);
assert.deepEqual(
uuidToBytes('226e4402-7ffc-4543-85c9-4622c50a5b14'),
expectedResult
);
assert.deepEqual(
uuidToBytes('226E4402-7FFC-4543-85C9-4622C50A5B14'),
expectedResult
);
});
it('returns an empty Uint8Array for strings of the wrong length', () => {
assert.deepEqual(uuidToBytes(''), new Uint8Array(0));
assert.deepEqual(uuidToBytes('abc'), new Uint8Array(0));
assert.deepEqual(
uuidToBytes('032deadf0d5e4ee78da28e75b1dfb284'),
new Uint8Array(0)
);
assert.deepEqual(
uuidToBytes('deaed5eb-d983-456a-a954-9ad7a006b271aaaaaaaaaa'),
new Uint8Array(0)
);
});
});
describe('bytesToUuid', () => {
it('converts valid Uint8Arrays to UUID strings', () => {
const buf = new Uint8Array([
0x22, 0x6e, 0x44, 0x02, 0x7f, 0xfc, 0x45, 0x43, 0x85, 0xc9, 0x46, 0x22,
0xc5, 0x0a, 0x5b, 0x14,
]);
assert.deepEqual(
bytesToUuid(buf),
'226e4402-7ffc-4543-85c9-4622c50a5b14'
);
});
it('returns undefined if passed an all-zero buffer', () => {
assert.isUndefined(bytesToUuid(new Uint8Array(16)));
});
it('returns undefined if passed the wrong number of bytes', () => {
assert.isUndefined(bytesToUuid(new Uint8Array(0)));
assert.isUndefined(bytesToUuid(new Uint8Array([0x22])));
assert.isUndefined(bytesToUuid(new Uint8Array(Array(17).fill(0x22))));
});
});
describe('attachments', () => {
const FILE_PATH = join(__dirname, '../../fixtures/ghost-kitty.mp4');
const FILE_CONTENTS = readFileSync(FILE_PATH);
const FILE_HASH = sha256(FILE_CONTENTS);
let tempDir: string;
beforeEach(async () => {
tempDir = await createTempDir();
});
afterEach(async () => {
if (tempDir) {
await deleteTempDir(log, tempDir);
}
});
it('v1 roundtrips (memory only)', () => {
const keys = generateAttachmentKeys();
// Note: support for padding is not in decryptAttachmentV1, so we don't pad here
const encryptedAttachment = encryptAttachment({
plaintext: FILE_CONTENTS,
keys,
});
const plaintext = decryptAttachmentV1(
encryptedAttachment.ciphertext,
keys,
encryptedAttachment.digest
);
assert.isTrue(constantTimeEqual(FILE_CONTENTS, plaintext));
});
it('v1 -> v2 (memory -> disk)', async () => {
const keys = generateAttachmentKeys();
const ciphertextPath = join(tempDir, 'file');
let plaintextPath;
try {
const encryptedAttachment = padAndEncryptAttachment({
plaintext: FILE_CONTENTS,
keys,
});
assert.strictEqual(encryptedAttachment.plaintextHash, GHOST_KITTY_HASH);
writeFileSync(ciphertextPath, encryptedAttachment.ciphertext);
const decryptedAttachment = await decryptAttachmentV2({
type: 'standard',
ciphertextPath,
idForLogging: 'test',
...splitKeys(keys),
size: FILE_CONTENTS.byteLength,
theirDigest: encryptedAttachment.digest,
getAbsoluteAttachmentPath:
window.Signal.Migrations.getAbsoluteAttachmentPath,
});
plaintextPath = window.Signal.Migrations.getAbsoluteAttachmentPath(
decryptedAttachment.path
);
const plaintext = readFileSync(plaintextPath);
assert.isTrue(constantTimeEqual(FILE_CONTENTS, plaintext));
assert.strictEqual(
encryptedAttachment.plaintextHash,
decryptedAttachment.plaintextHash
);
} finally {
if (plaintextPath) {
unlinkSync(plaintextPath);
}
}
});
describe('v2 roundtrips', () => {
async function testV2RoundTripData({
path,
data,
plaintextHash,
encryptionKeys,
dangerousIv,
}: {
path?: string;
data: Uint8Array;
plaintextHash: Uint8Array;
encryptionKeys?: Uint8Array;
dangerousIv?: HardcodedIVForEncryptionType;
}): Promise<void> {
let plaintextPath;
let ciphertextPath;
const keys = encryptionKeys ?? generateAttachmentKeys();
try {
const encryptedAttachment = await encryptAttachmentV2ToDisk({
keys,
plaintext: path ? { absolutePath: path } : { data },
dangerousIv,
getAbsoluteAttachmentPath:
window.Signal.Migrations.getAbsoluteAttachmentPath,
});
ciphertextPath = window.Signal.Migrations.getAbsoluteAttachmentPath(
encryptedAttachment.path
);
const decryptedAttachment = await decryptAttachmentV2({
type: 'standard',
ciphertextPath,
idForLogging: 'test',
...splitKeys(keys),
size: data.byteLength,
theirDigest: encryptedAttachment.digest,
getAbsoluteAttachmentPath:
window.Signal.Migrations.getAbsoluteAttachmentPath,
});
plaintextPath = window.Signal.Migrations.getAbsoluteAttachmentPath(
decryptedAttachment.path
);
const plaintext = readFileSync(plaintextPath);
assert.deepStrictEqual(
encryptedAttachment.iv,
decryptedAttachment.iv
);
if (dangerousIv) {
assert.deepStrictEqual(encryptedAttachment.iv, dangerousIv.iv);
if (dangerousIv.reason === 'reencrypting-for-backup') {
assert.deepStrictEqual(
encryptedAttachment.digest,
dangerousIv.digestToMatch
);
}
}
assert.isTrue(constantTimeEqual(data, plaintext));
assert.strictEqual(
encryptedAttachment.ciphertextSize,
getAttachmentCiphertextLength(data.byteLength)
);
assert.strictEqual(
encryptedAttachment.plaintextHash,
Bytes.toHex(plaintextHash)
);
assert.strictEqual(
decryptedAttachment.plaintextHash,
encryptedAttachment.plaintextHash
);
} finally {
if (plaintextPath) {
unlinkSync(plaintextPath);
}
if (ciphertextPath) {
unlinkSync(ciphertextPath);
}
}
}
it('v2 roundtrips smaller file from disk', async () => {
await testV2RoundTripData({
path: FILE_PATH,
data: FILE_CONTENTS,
plaintextHash: FILE_HASH,
});
});
it('v2 roundtrips smaller file from memory', async () => {
await testV2RoundTripData({
data: FILE_CONTENTS,
plaintextHash: FILE_HASH,
});
// also works if data is raw Uint8Array rather than a buffer
await testV2RoundTripData({
data: new Uint8Array(FILE_CONTENTS),
plaintextHash: FILE_HASH,
});
});
it('v2 roundtrips large file from disk', async () => {
const sourcePath = join(tempDir, 'random');
// Get sufficient large file to have more than 64kb of padding and
// trigger push back on the streams.
const data = getRandomBytes(5 * 1024 * 1024);
const plaintextHash = sha256(data);
writeFileSync(sourcePath, data);
try {
await testV2RoundTripData({
path: sourcePath,
data,
plaintextHash,
});
} finally {
unlinkSync(sourcePath);
}
});
it('v2 roundtrips large file from memory', async () => {
// Get sufficient large data to have more than 64kb of padding and
// trigger push back on the streams.
const data = getRandomBytes(5 * 1024 * 1024);
const plaintextHash = sha256(data);
await testV2RoundTripData({
data,
plaintextHash,
});
});
describe('dangerousIv', () => {
it('uses hardcodedIv in tests', async () => {
await testV2RoundTripData({
data: FILE_CONTENTS,
plaintextHash: FILE_HASH,
dangerousIv: {
reason: 'test',
iv: _generateAttachmentIv(),
},
});
});
it('uses hardcodedIv when re-encrypting for backup', async () => {
const keys = generateAttachmentKeys();
const previouslyEncrypted = await encryptAttachmentV2ToDisk({
keys,
plaintext: { data: FILE_CONTENTS },
getAbsoluteAttachmentPath:
window.Signal.Migrations.getAbsoluteAttachmentPath,
});
await testV2RoundTripData({
data: FILE_CONTENTS,
plaintextHash: FILE_HASH,
encryptionKeys: keys,
dangerousIv: {
reason: 'reencrypting-for-backup',
iv: previouslyEncrypted.iv,
digestToMatch: previouslyEncrypted.digest,
},
});
// If the digest is wrong, it should throw
await assert.isRejected(
testV2RoundTripData({
data: FILE_CONTENTS,
plaintextHash: FILE_HASH,
encryptionKeys: keys,
dangerousIv: {
reason: 'reencrypting-for-backup',
iv: previouslyEncrypted.iv,
digestToMatch: getRandomBytes(32),
},
}),
'iv was hardcoded for backup re-encryption, but digest does not match'
);
});
});
});
it('v2 -> v1 (disk -> memory)', async () => {
const keys = generateAttachmentKeys();
let ciphertextPath;
try {
const encryptedAttachment = await encryptAttachmentV2ToDisk({
keys,
plaintext: { absolutePath: FILE_PATH },
getAbsoluteAttachmentPath:
window.Signal.Migrations.getAbsoluteAttachmentPath,
});
ciphertextPath = window.Signal.Migrations.getAbsoluteAttachmentPath(
encryptedAttachment.path
);
const ciphertext = readFileSync(ciphertextPath);
const plaintext = decryptAttachmentV1(
ciphertext,
keys,
encryptedAttachment.digest
);
const IV = 16;
const MAC = 32;
const PADDING_FOR_GHOST_KITTY = 126_066; // delta between file size and next bucket
assert.strictEqual(
plaintext.byteLength,
FILE_CONTENTS.byteLength + IV + MAC + PADDING_FOR_GHOST_KITTY,
'verify padding'
);
// Note: support for padding is not in decryptAttachmentV1, so we manually unpad
const plaintextWithoutPadding = plaintext.subarray(
0,
FILE_CONTENTS.byteLength
);
assert.isTrue(
constantTimeEqual(FILE_CONTENTS, plaintextWithoutPadding)
);
} finally {
if (ciphertextPath) {
unlinkSync(ciphertextPath);
}
}
});
it('v1 and v2 produce the same ciphertext, given same iv', async () => {
const keys = generateAttachmentKeys();
const dangerousTestOnlyIv = _generateAttachmentIv();
let ciphertextPath;
try {
const encryptedAttachmentV1 = padAndEncryptAttachment({
plaintext: FILE_CONTENTS,
keys,
dangerousTestOnlyIv,
});
const ciphertextV1 = encryptedAttachmentV1.ciphertext;
const encryptedAttachmentV2 = await encryptAttachmentV2ToDisk({
keys,
plaintext: { absolutePath: FILE_PATH },
dangerousIv: { iv: dangerousTestOnlyIv, reason: 'test' },
getAbsoluteAttachmentPath:
window.Signal.Migrations.getAbsoluteAttachmentPath,
});
ciphertextPath = window.Signal.Migrations.getAbsoluteAttachmentPath(
encryptedAttachmentV2.path
);
const ciphertextV2 = readFileSync(ciphertextPath);
assert.strictEqual(ciphertextV1.byteLength, ciphertextV2.byteLength);
assert.isTrue(constantTimeEqual(ciphertextV1, ciphertextV2));
} finally {
if (ciphertextPath) {
unlinkSync(ciphertextPath);
}
}
});
describe('decryptAttachmentV2 with outer layer of encryption', () => {
async function doubleEncrypt({
plaintextAbsolutePath,
innerKeys,
outerKeys,
}: {
plaintextAbsolutePath: string;
innerKeys: Uint8Array;
outerKeys: Uint8Array;
}) {
let innerCiphertextPath;
let outerCiphertextPath;
let innerEncryptedAttachment;
try {
innerEncryptedAttachment = await encryptAttachmentV2ToDisk({
keys: innerKeys,
plaintext: { absolutePath: plaintextAbsolutePath },
getAbsoluteAttachmentPath:
window.Signal.Migrations.getAbsoluteAttachmentPath,
});
innerCiphertextPath =
window.Signal.Migrations.getAbsoluteAttachmentPath(
innerEncryptedAttachment.path
);
const outerEncryptedAttachment = await encryptAttachmentV2ToDisk({
keys: outerKeys,
plaintext: { absolutePath: innerCiphertextPath },
// We (and the server!) don't pad the second layer
dangerousTestOnlySkipPadding: true,
getAbsoluteAttachmentPath:
window.Signal.Migrations.getAbsoluteAttachmentPath,
});
outerCiphertextPath =
window.Signal.Migrations.getAbsoluteAttachmentPath(
outerEncryptedAttachment.path
);
} finally {
if (innerCiphertextPath) {
unlinkSync(innerCiphertextPath);
}
}
return {
outerCiphertextPath,
innerEncryptedAttachment,
};
}
it('v2 roundtrips smaller file (all on disk)', async () => {
const outerKeys = generateAttachmentKeys();
const innerKeys = generateAttachmentKeys();
let plaintextPath;
let outerCiphertextPath;
try {
const encryptResult = await doubleEncrypt({
plaintextAbsolutePath: FILE_PATH,
innerKeys,
outerKeys,
});
outerCiphertextPath = encryptResult.outerCiphertextPath;
const decryptedAttachment = await decryptAttachmentV2({
type: 'standard',
ciphertextPath: outerCiphertextPath,
idForLogging: 'test',
...splitKeys(innerKeys),
size: FILE_CONTENTS.byteLength,
theirDigest: encryptResult.innerEncryptedAttachment.digest,
outerEncryption: splitKeys(outerKeys),
getAbsoluteAttachmentPath:
window.Signal.Migrations.getAbsoluteAttachmentPath,
});
plaintextPath = window.Signal.Migrations.getAbsoluteAttachmentPath(
decryptedAttachment.path
);
const plaintext = readFileSync(plaintextPath);
assert.isTrue(constantTimeEqual(FILE_CONTENTS, plaintext));
assert.strictEqual(
encryptResult.innerEncryptedAttachment.plaintextHash,
GHOST_KITTY_HASH
);
assert.strictEqual(
decryptedAttachment.plaintextHash,
encryptResult.innerEncryptedAttachment.plaintextHash
);
} finally {
if (plaintextPath) {
unlinkSync(plaintextPath);
}
if (outerCiphertextPath) {
unlinkSync(outerCiphertextPath);
}
}
});
it('v2 roundtrips random data (all on disk)', async () => {
const sourcePath = join(tempDir, 'random');
// Get sufficient large file to have more than 64kb of padding and
// trigger push back on the streams.
const data = getRandomBytes(5 * 1024 * 1024);
writeFileSync(sourcePath, data);
const outerKeys = generateAttachmentKeys();
const innerKeys = generateAttachmentKeys();
let plaintextPath;
let outerCiphertextPath;
try {
const encryptResult = await doubleEncrypt({
plaintextAbsolutePath: sourcePath,
innerKeys,
outerKeys,
});
outerCiphertextPath = encryptResult.outerCiphertextPath;
const decryptedAttachment = await decryptAttachmentV2({
type: 'standard',
ciphertextPath: outerCiphertextPath,
idForLogging: 'test',
...splitKeys(innerKeys),
size: data.byteLength,
theirDigest: encryptResult.innerEncryptedAttachment.digest,
outerEncryption: splitKeys(outerKeys),
getAbsoluteAttachmentPath:
window.Signal.Migrations.getAbsoluteAttachmentPath,
});
plaintextPath = window.Signal.Migrations.getAbsoluteAttachmentPath(
decryptedAttachment.path
);
const plaintext = readFileSync(plaintextPath);
assert.isTrue(constantTimeEqual(data, plaintext));
} finally {
if (sourcePath) {
unlinkSync(sourcePath);
}
if (plaintextPath) {
unlinkSync(plaintextPath);
}
if (outerCiphertextPath) {
unlinkSync(outerCiphertextPath);
}
}
});
it('v2 fails if outer encryption mac is wrong', async () => {
const sourcePath = join(tempDir, 'random');
// Get sufficient large file to have more than 64kb of padding and
// trigger push back on the streams.
const data = getRandomBytes(5 * 1024 * 1024);
writeFileSync(sourcePath, data);
const outerKeys = generateAttachmentKeys();
const innerKeys = generateAttachmentKeys();
let outerCiphertextPath;
try {
const encryptResult = await doubleEncrypt({
plaintextAbsolutePath: sourcePath,
innerKeys,
outerKeys,
});
outerCiphertextPath = encryptResult.outerCiphertextPath;
await assert.isRejected(
decryptAttachmentV2({
type: 'standard',
ciphertextPath: outerCiphertextPath,
idForLogging: 'test',
...splitKeys(innerKeys),
size: data.byteLength,
theirDigest: encryptResult.innerEncryptedAttachment.digest,
outerEncryption: {
aesKey: splitKeys(outerKeys).aesKey,
macKey: splitKeys(innerKeys).macKey, // wrong mac!
},
getAbsoluteAttachmentPath:
window.Signal.Migrations.getAbsoluteAttachmentPath,
}),
/Bad outer encryption MAC/
);
} finally {
if (sourcePath) {
unlinkSync(sourcePath);
}
if (outerCiphertextPath) {
unlinkSync(outerCiphertextPath);
}
}
});
});
});
describe('getAesCbcCiphertextLength', () => {
function encrypt(length: number) {
const cipher = createCipheriv(
CipherType.AES256CBC,
getRandomBytes(32),
getRandomBytes(16)
);
const encrypted = cipher.update(Buffer.alloc(length));
return Buffer.concat([encrypted, cipher.final()]);
}
it('calculates cipherTextLength correctly', () => {
for (let i = 0; i < 128; i += 1) {
assert.strictEqual(getAesCbcCiphertextLength(i), encrypt(i).length);
}
});
});
});