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rewrite MegolmExportEncryption using async/await 

... to make it easier to add exception handling
pull/21833/head
Richard van der Hoff 2017-06-08 07:54:47 +01:00
parent 34e4d8088b
commit b16e652acc
2 changed files with 112 additions and 105 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

51
src/utils/MegolmExportEncryption.js
View File

@ -36,7 +36,7 @@ const subtleCrypto = window.crypto.subtle || window.crypto.webkitSubtle;
* @param {String} password
* @return {Promise<String>} promise for decrypted output
*/
export function decryptMegolmKeyFile(data, password) {
export async function decryptMegolmKeyFile(data, password) {
const body = unpackMegolmKeyFile(data);
// check we have a version byte
@ -60,21 +60,20 @@ export function decryptMegolmKeyFile(data, password) {
const ciphertext = body.subarray(37, 37+ciphertextLength);
const hmac = body.subarray(-32);
return deriveKeys(salt, iterations, password).then((keys) => {
const [aesKey, hmacKey] = keys;
const [aesKey, hmacKey] = await deriveKeys(salt, iterations, password);
const toVerify = body.subarray(0, -32);
return subtleCrypto.verify(
const isValid = await subtleCrypto.verify(
{name: 'HMAC'},
hmacKey,
hmac,
toVerify,
).then((isValid) => {
);
if (!isValid) {
throw new Error('Authentication check failed: incorrect password?');
}
return subtleCrypto.decrypt(
const plaintext = await subtleCrypto.decrypt(
{
name: "AES-CTR",
counter: iv,
@ -83,10 +82,8 @@ export function decryptMegolmKeyFile(data, password) {
aesKey,
ciphertext,
);
});
}).then((plaintext) => {
return new TextDecoder().decode(new Uint8Array(plaintext));
});
}
@ -100,7 +97,7 @@ export function decryptMegolmKeyFile(data, password) {
* key-derivation function.
* @return {Promise<ArrayBuffer>} promise for encrypted output
*/
export function encryptMegolmKeyFile(data, password, options) {
export async function encryptMegolmKeyFile(data, password, options) {
options = options || {};
const kdfRounds = options.kdf_rounds || 500000;
@ -115,10 +112,9 @@ export function encryptMegolmKeyFile(data, password, options) {
// of a single bit of iv is a price we have to pay.
iv[9] &= 0x7f;
return deriveKeys(salt, kdfRounds, password).then((keys) => {
const [aesKey, hmacKey] = keys;
const [aesKey, hmacKey] = await deriveKeys(salt, kdfRounds, password);
return subtleCrypto.encrypt(
const ciphertext = await subtleCrypto.encrypt(
{
name: "AES-CTR",
counter: iv,
@ -126,7 +122,8 @@ export function encryptMegolmKeyFile(data, password, options) {
},
aesKey,
new TextEncoder().encode(data),
).then((ciphertext) => {
);
const cipherArray = new Uint8Array(ciphertext);
const bodyLength = (1+salt.length+iv.length+4+cipherArray.length+32);
const resultBuffer = new Uint8Array(bodyLength);
@ -142,17 +139,15 @@ export function encryptMegolmKeyFile(data, password, options) {
const toSign = resultBuffer.subarray(0, idx);
return subtleCrypto.sign(
const hmac = await subtleCrypto.sign(
{name: 'HMAC'},
hmacKey,
toSign,
).then((hmac) => {
hmac = new Uint8Array(hmac);
resultBuffer.set(hmac, idx);
);
const hmacArray = new Uint8Array(hmac);
resultBuffer.set(hmacArray, idx);
return packMegolmKeyFile(resultBuffer);
});
});
});
}
/**
@ -163,16 +158,17 @@ export function encryptMegolmKeyFile(data, password, options) {
* @param {String} password password
* @return {Promise<[CryptoKey, CryptoKey]>} promise for [aes key, hmac key]
*/
function deriveKeys(salt, iterations, password) {
async function deriveKeys(salt, iterations, password) {
const start = new Date();
return subtleCrypto.importKey(
const key = await subtleCrypto.importKey(
'raw',
new TextEncoder().encode(password),
{name: 'PBKDF2'},
false,
['deriveBits'],
).then((key) => {
return subtleCrypto.deriveBits(
);
const keybits = await subtleCrypto.deriveBits(
{
name: 'PBKDF2',
salt: salt,
@ -182,7 +178,7 @@ function deriveKeys(salt, iterations, password) {
key,
512,
);
}).then((keybits) => {
const now = new Date();
console.log("E2e import/export: deriveKeys took " + (now - start) + "ms");
@ -206,8 +202,7 @@ function deriveKeys(salt, iterations, password) {
false,
['sign', 'verify'],
);
return Promise.all([aesProm, hmacProm]);
});
return await Promise.all([aesProm, hmacProm]);
}
const HEADER_LINE = '-----BEGIN MEGOLM SESSION DATA-----';

24
test/utils/MegolmExportEncryption-test.js
View File

@ -81,15 +81,23 @@ describe('MegolmExportEncryption', function() {
describe('decrypt', function() {
it('should handle missing header', function() {
const input=stringToArray(`-----`);
expect(()=>MegolmExportEncryption.decryptMegolmKeyFile(input, ''))
.toThrow('Header line not found');
return MegolmExportEncryption.decryptMegolmKeyFile(input, '')
.then((res) => {
throw new Error('expected to throw');
}, (error) => {
expect(error.message).toEqual('Header line not found');
});
});
it('should handle missing trailer', function() {
const input=stringToArray(`-----BEGIN MEGOLM SESSION DATA-----
-----`);
expect(()=>MegolmExportEncryption.decryptMegolmKeyFile(input, ''))
.toThrow('Trailer line not found');
return MegolmExportEncryption.decryptMegolmKeyFile(input, '')
.then((res) => {
throw new Error('expected to throw');
}, (error) => {
expect(error.message).toEqual('Trailer line not found');
});
});
it('should handle a too-short body', function() {
@ -98,8 +106,12 @@ AXNhbHRzYWx0c2FsdHNhbHSIiIiIiIiIiIiIiIiIiIiIAAAACmIRUW2OjZ3L2l6j9h0lHlV3M2dx
cissyYBxjsfsAn
-----END MEGOLM SESSION DATA-----
`);
expect(()=>MegolmExportEncryption.decryptMegolmKeyFile(input, ''))
.toThrow('Invalid file: too short');
return MegolmExportEncryption.decryptMegolmKeyFile(input, '')
.then((res) => {
throw new Error('expected to throw');
}, (error) => {
expect(error.message).toEqual('Invalid file: too short');
});
});
it('should decrypt a range of inputs', function(done) {