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Finish up webcrypto integration, Fixes #72

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We now correctly and opportunistically use the webcrypto API if
available, polyfilling if it's not detected. This change also includes a
layer of abstraction over the webcrypto interface so we no longer have
to deal with key-imports or algorithm names all over the place. Since we
no longer support AES-CTR, code outside this file can simply call
`textsecure.subtle.<encrypt|decrypt|sign>(key, data [, iv])`.
This commit is contained in:
lilia 2014-10-26 20:02:11 -07:00
parent 244e051fc3
commit 39505c81b1
3 changed files with 104 additions and 90 deletions
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14
js/crypto.js
View file

@ -60,7 +60,7 @@ window.textsecure.crypto = function() {
}
function HmacSHA256(key, input) {
return window.textsecure.subtle.sign({name: "HMAC", hash: "SHA-256"}, key, input);
return window.textsecure.subtle.sign(key, input);
}
testing_only.privToPub = function(privKey, isIdentity) {
@ -690,7 +690,7 @@ window.textsecure.crypto = function() {
macInput.set(new Uint8Array(messageProtoArray), 33*2 + 1);
return verifyMAC(macInput.buffer, keys[1], mac).then(function() {
return window.textsecure.subtle.decrypt({name: "AES-CBC", iv: keys[2].slice(0, 16)}, keys[0], toArrayBuffer(message.ciphertext))
return window.textsecure.subtle.decrypt(keys[0], toArrayBuffer(message.ciphertext), keys[2].slice(0, 16))
.then(function(paddedPlaintext) {
paddedPlaintext = new Uint8Array(paddedPlaintext);
@ -743,7 +743,7 @@ window.textsecure.crypto = function() {
var mac = decodedMessage.slice(decodedMessage.byteLength - 10, decodedMessage.byteLength);
return verifyMAC(ivAndCiphertext, mac_key, mac).then(function() {
return window.textsecure.subtle.decrypt({name: "AES-CBC", iv: iv}, aes_key, ciphertext);
return window.textsecure.subtle.decrypt(aes_key, ciphertext, iv);
});
};
@ -757,7 +757,7 @@ window.textsecure.crypto = function() {
var mac = encryptedBin.slice(encryptedBin.byteLength - 32, encryptedBin.byteLength);
return verifyMAC(ivAndCiphertext, mac_key, mac).then(function() {
return window.textsecure.subtle.decrypt({name: "AES-CBC", iv: iv}, aes_key, ciphertext);
return window.textsecure.subtle.decrypt(aes_key, ciphertext, iv);
});
};
@ -765,7 +765,7 @@ window.textsecure.crypto = function() {
var aes_key = keys.slice(0, 32);
var mac_key = keys.slice(32, 64);
return window.textsecure.subtle.encrypt({name: "AES-CBC", iv: iv}, aes_key, plaintext).then(function(ciphertext) {
return window.textsecure.subtle.encrypt(aes_key, plaintext, iv).then(function(ciphertext) {
var ivAndCiphertext = new Uint8Array(16 + ciphertext.byteLength);
ivAndCiphertext.set(new Uint8Array(iv));
ivAndCiphertext.set(new Uint8Array(ciphertext), 16);
@ -819,7 +819,7 @@ window.textsecure.crypto = function() {
msg.counter = chain.chainKey.counter;
msg.previousCounter = session.currentRatchet.previousCounter;
return window.textsecure.subtle.encrypt({name: "AES-CBC", iv: keys[2].slice(0, 16)}, keys[0], paddedPlaintext.buffer).then(function(ciphertext) {
return window.textsecure.subtle.encrypt(keys[0], paddedPlaintext.buffer, keys[2].slice(0, 16)).then(function(ciphertext) {
msg.ciphertext = ciphertext;
var encodedMsg = toArrayBuffer(msg.encode());
@ -958,7 +958,7 @@ window.textsecure.crypto = function() {
var ciphertext = message.slice(16 + 1, message.length - 32);
return verifyMAC(ivAndCiphertext, ecRes[1], mac).then(function() {
window.textsecure.subtle.decrypt({name: "AES-CBC", iv: iv}, ecRes[0], ciphertext).then(function(plaintext) {
window.textsecure.subtle.decrypt(ecRes[0], ciphertext, iv).then(function(plaintext) {
var identityKeyMsg = textsecure.protobuf.IdentityKey.decode(plaintext);
privToPub(toArrayBuffer(identityKeyMsg.identityKey)).then(function(identityKeyPair) {

24
js/test.js
View file

@ -35,11 +35,9 @@ describe("Cryptographic primitives", function() {
var iv = hexToArrayBuffer('000102030405060708090a0b0c0d0e0f');
var plaintext = hexToArrayBuffer('6bc1bee22e409f96e93d7e117393172aae2d8a571e03ac9c9eb76fac45af8e5130c81c46a35ce411e5fbc1191a0a52eff69f2445df4f9b17ad2b417be66c3710');
var ciphertext = hexToArrayBuffer('f58c4c04d6e5f1ba779eabfb5f7bfbd69cfc4e967edb808d679f777bc6702c7d39f23369a9d9bacfa530e26304231461b2eb05e2c39be9fcda6c19078c6a9d1b3f461796d6b0d6b2e0c2a72b4d80e644');
window.textsecure.subtle.importKey('raw', key, {name: 'AES-CBC'}, true, ['encrypt']).then(function(key) {
return window.textsecure.subtle.encrypt({name: 'AES-CBC', iv: new Uint8Array(iv)}, key, plaintext).then(function(result) {
assert.strictEqual(getString(result), getString(ciphertext));
}).then(done).catch(done);
}).catch(done);
window.textsecure.subtle.encrypt(key, plaintext, iv).then(function(result) {
assert.strictEqual(getString(result), getString(ciphertext));
}).then(done).catch(done);
});
});
@ -49,11 +47,9 @@ describe("Cryptographic primitives", function() {
var iv = hexToArrayBuffer('000102030405060708090a0b0c0d0e0f');
var plaintext = hexToArrayBuffer('6bc1bee22e409f96e93d7e117393172aae2d8a571e03ac9c9eb76fac45af8e5130c81c46a35ce411e5fbc1191a0a52eff69f2445df4f9b17ad2b417be66c3710');
var ciphertext = hexToArrayBuffer('f58c4c04d6e5f1ba779eabfb5f7bfbd69cfc4e967edb808d679f777bc6702c7d39f23369a9d9bacfa530e26304231461b2eb05e2c39be9fcda6c19078c6a9d1b3f461796d6b0d6b2e0c2a72b4d80e644');
window.textsecure.subtle.importKey('raw', key, {name: 'AES-CBC'}, true, ['decrypt']).then(function(key) {
return window.textsecure.subtle.decrypt({name: 'AES-CBC', iv: new Uint8Array(iv)}, key, ciphertext).then(function(result) {
assert.strictEqual(getString(result), getString(plaintext));
}).then(done).catch(done);
}).catch(done);
window.textsecure.subtle.decrypt(key, ciphertext, iv).then(function(result) {
assert.strictEqual(getString(result), getString(plaintext));
}).then(done).catch(done);
});
});
@ -62,11 +58,9 @@ describe("Cryptographic primitives", function() {
var key = hexToArrayBuffer('6f35628d65813435534b5d67fbdb54cb33403d04e843103e6399f806cb5df95febbdd61236f33245');
var input = hexToArrayBuffer('752cff52e4b90768558e5369e75d97c69643509a5e5904e0a386cbe4d0970ef73f918f675945a9aefe26daea27587e8dc909dd56fd0468805f834039b345f855cfe19c44b55af241fff3ffcd8045cd5c288e6c4e284c3720570b58e4d47b8feeedc52fd1401f698a209fccfa3b4c0d9a797b046a2759f82a54c41ccd7b5f592b');
var mac = getString(hexToArrayBuffer('05d1243e6465ed9620c9aec1c351a186'));
window.textsecure.subtle.importKey('raw', key, {name: 'HMAC', hash: {name: 'SHA-256'}}, true, ['sign']).then(function(key) {
return window.textsecure.subtle.sign({name: 'HMAC', hash: 'SHA-256'}, key, input).then(function(result) {
assert.strictEqual(getString(result).substring(0, mac.length), mac);
}).then(done).catch(done);
}).catch(done);
window.textsecure.subtle.sign(key, input).then(function(result) {
assert.strictEqual(getString(result).substring(0, mac.length), mac);
}).then(done).catch(done);
});
});

156
js/webcrypto.js
View file

@ -13,78 +13,98 @@
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
// All inputs/outputs are arraybuffers!
window.textsecure.subtle = (function() {
var StaticArrayBufferProto = new ArrayBuffer().__proto__;
function assertIsArrayBuffer(thing) {
if (thing !== Object(thing) || thing.__proto__ != StaticArrayBufferProto)
throw new Error("Needed a ArrayBuffer");
}
'use strict';
;(function() {
// Test for webcrypto support, polyfill if needed.
if (window.crypto.subtle === undefined || window.crypto.subtle === null) {
window.crypto.subtle = (function() {
var StaticArrayBufferProto = new ArrayBuffer().__proto__;
function assertIsArrayBuffer(thing) {
if (thing !== Object(thing) || thing.__proto__ != StaticArrayBufferProto)
throw new Error("Needed a ArrayBuffer");
}
// private implementation functions
function HmacSHA256(key, input) {
assertIsArrayBuffer(key);
assertIsArrayBuffer(input);
return CryptoJS.HmacSHA256(
CryptoJS.lib.WordArray.create(input),
CryptoJS.enc.Latin1.parse(getString(key))
).toString(CryptoJS.enc.Latin1);
};
// Synchronous implementation functions for polyfilling webcrypto
// All inputs/outputs are arraybuffers!
function HmacSHA256(key, input) {
assertIsArrayBuffer(key);
assertIsArrayBuffer(input);
return CryptoJS.HmacSHA256(
CryptoJS.lib.WordArray.create(input),
CryptoJS.enc.Latin1.parse(getString(key))
).toString(CryptoJS.enc.Latin1);
};
function encryptAESCBC(plaintext, key, iv) {
assertIsArrayBuffer(plaintext);
assertIsArrayBuffer(key);
assertIsArrayBuffer(iv);
return CryptoJS.AES.encrypt(CryptoJS.enc.Latin1.parse(getString(plaintext)),
CryptoJS.enc.Latin1.parse(getString(key)),
{iv: CryptoJS.enc.Latin1.parse(getString(iv))})
.ciphertext.toString(CryptoJS.enc.Latin1);
};
function encryptAESCBC(plaintext, key, iv) {
assertIsArrayBuffer(plaintext);
assertIsArrayBuffer(key);
assertIsArrayBuffer(iv);
return CryptoJS.AES.encrypt(
CryptoJS.enc.Latin1.parse(getString(plaintext)),
CryptoJS.enc.Latin1.parse(getString(key)),
{ iv: CryptoJS.enc.Latin1.parse(getString(iv)) }
).ciphertext.toString(CryptoJS.enc.Latin1);
};
function decryptAESCBC(ciphertext, key, iv) {
assertIsArrayBuffer(ciphertext);
assertIsArrayBuffer(key);
assertIsArrayBuffer(iv);
return CryptoJS.AES.decrypt(btoa(getString(ciphertext)),
CryptoJS.enc.Latin1.parse(getString(key)),
{iv: CryptoJS.enc.Latin1.parse(getString(iv))})
.toString(CryptoJS.enc.Latin1);
};
function decryptAESCBC(ciphertext, key, iv) {
assertIsArrayBuffer(ciphertext);
assertIsArrayBuffer(key);
assertIsArrayBuffer(iv);
return CryptoJS.AES.decrypt(
btoa(getString(ciphertext)),
CryptoJS.enc.Latin1.parse(getString(key)),
{ iv: CryptoJS.enc.Latin1.parse(getString(iv)) }
).toString(CryptoJS.enc.Latin1);
};
// utility function for connecting front and back ends via promises
// Takes an implementation function and 0 or more arguments
function promise(implementation) {
var args = Array.prototype.slice.call(arguments);
args.shift();
return Promise.resolve(toArrayBuffer(implementation.apply(this, args)));
}
// utility function for connecting front and back ends via promises
// Takes an implementation function and 0 or more arguments
function promise(implementation) {
var args = Array.prototype.slice.call(arguments);
args.shift();
return new Promise(function(resolve) {
resolve(toArrayBuffer(implementation.apply(this, args)));
});
};
// public interface functions
function encrypt(algorithm, key, data) {
if (algorithm.name === "AES-CTR")
return promise(encryptAESCTR, data, key, algorithm.counter);
if (algorithm.name === "AES-CBC")
return promise(encryptAESCBC, data, key, algorithm.iv.buffer || algorithm.iv);
return {
encrypt: function(algorithm, key, data) {
if (algorithm.name === "AES-CBC")
return promise(encryptAESCBC, data, key, algorithm.iv.buffer || algorithm.iv);
},
decrypt: function(algorithm, key, data) {
if (algorithm.name === "AES-CBC")
return promise(decryptAESCBC, data, key, algorithm.iv.buffer || algorithm.iv);
},
sign: function(algorithm, key, data) {
if (algorithm.name === "HMAC" && algorithm.hash === "SHA-256")
return promise(HmacSHA256, key, data);
},
importKey: function(format, key, algorithm, extractable, usages) {
return new Promise(function(resolve,reject){ resolve(key); });
}
};
})();
} // if !window.crypto.subtle
window.textsecure.subtle = {
encrypt: function(key, data, iv) {
return window.crypto.subtle.importKey('raw', key, {name: 'AES-CBC'}, false, ['encrypt']).then(function(key) {
return window.crypto.subtle.encrypt({name: 'AES-CBC', iv: new Uint8Array(iv)}, key, data);
});
},
decrypt: function(key, data, iv) {
return window.crypto.subtle.importKey('raw', key, {name: 'AES-CBC'}, false, ['decrypt']).then(function(key) {
return window.crypto.subtle.decrypt({name: 'AES-CBC', iv: new Uint8Array(iv)}, key, data);
});
},
sign: function(key, data) {
return window.crypto.subtle.importKey('raw', key, {name: 'HMAC', hash: {name: 'SHA-256'}}, false, ['sign']).then(function(key) {
return window.crypto.subtle.sign( {name: 'HMAC', hash: 'SHA-256'}, key, data);
});
},
};
function decrypt(algorithm, key, data) {
if (algorithm.name === "AES-CTR")
return promise(decryptAESCTR, data, key, algorithm.counter);
if (algorithm.name === "AES-CBC")
return promise(decryptAESCBC, data, key, algorithm.iv.buffer || algorithm.iv);
};
function sign(algorithm, key, data) {
if (algorithm.name === "HMAC" && algorithm.hash === "SHA-256")
return promise(HmacSHA256, key, data);
};
function importKey(format, key, algorithm, extractable, usages) {
return new Promise(function(resolve,reject){ resolve(key); });
};
return {
encrypt : encrypt,
decrypt : decrypt,
sign : sign,
importKey : importKey,
}
})();