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Update p2p call encryptor
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evgeny-nadymov committed Apr 22, 2021
1 parent 42eb15a commit eb4daa2
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Showing 2 changed files with 244 additions and 25 deletions.
262 changes: 240 additions & 22 deletions src/Calls/P2P/P2PEncryptor.js
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Expand Up @@ -7,49 +7,267 @@

import CryptoJS from 'crypto-js';

const P2P_ENCRYPTION = false;
const P2P_ENCRYPTION = true;

const kMaxIncomingPacketSize = 128 * 1024 * 1024;

function uint8ArrayToWordArray(u8arr) {
let len = u8arr.length;
let words = [];
for (let i = 0; i < len; i++) {
words[i >>> 2] |= (u8arr[i] & 0xff) << (24 - (i % 4) * 8);
}

return CryptoJS.lib.WordArray.create(words, len);
}

function wordArrayToUint8Array(wordArray) {
const l = wordArray.sigBytes;
const words = wordArray.words;
const result = new Uint8Array(l);

let i = 0 /*dst*/, j = 0 /*src*/;
while(true) {
// here i is a multiple of 4
if (i===l)
break;
let w = words[j++];
result[i++] = (w & 0xff000000) >>> 24;
if (i===l)
break;
result[i++] = (w & 0x00ff0000) >>> 16;
if (i===l)
break;
result[i++] = (w & 0x0000ff00) >>> 8;
if (i===l)
break;
result[i++] = (w & 0x000000ff);
}

return result;
}

export default class P2PEncryptor {
constructor(key, isOutgoing) {
const p2pKey = CryptoJS.enc.Base64.parse(key);
constructor(isOutgoing, keyBase64) {
this.keyBase64 = keyBase64;
this.isOutgoing = isOutgoing;
this.type = 'Signaling';
this.counter = 0;

this.key = CryptoJS.enc.Hex.parse('3132333435363738393031323334353641424344454647484940414243444546');
this.iv = CryptoJS.enc.Hex.parse('0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f');
this.mode = CryptoJS.mode.CTR;
this.padding = CryptoJS.pad.NoPadding;
const p2pKeyWA = CryptoJS.enc.Base64.parse(keyBase64);
this.p2pKey = wordArrayToUint8Array(p2pKeyWA);
}

encryptToBase64(str) {
if (P2P_ENCRYPTION) {
const { key, iv, mode, padding } = this;
const enc = new TextEncoder();
const arr = enc.encode(str);

const encrypted = CryptoJS.AES.encrypt(str, key, {
mode,
iv,
padding
});
const packet = this.encryptRawPacket(new Uint8Array(arr));

const { bytes } = packet;
const wa = uint8ArrayToWordArray(bytes);

return encrypted.toString();
return CryptoJS.enc.Base64.stringify(wa);
} else {
// to base64 string
return btoa(str);
}
}

decryptFromBase64(base64) {
if (P2P_ENCRYPTION) {
const { key, iv, mode, padding } = this;
const wa = CryptoJS.enc.Base64.parse(base64);

const buffer = wordArrayToUint8Array(wa);
const decrypted = this.decryptRawPacket(buffer);

const dec = new TextDecoder('utf-8');
return dec.decode(decrypted);
} else {
return atob(base64);
}
}

concatSHA256(parts) {
const sha256 = CryptoJS.algo.SHA256.create();
const dec = new TextDecoder('utf-8')
for (let i = 0; i < parts.length; i++) {
const str = dec.decode(parts[i]);
sha256.update(str);
}

const result = sha256.finalize();

return wordArrayToUint8Array(result);
}

encryptPrepared(buffer) {
const result = {
counter: 0, //this.counterFromSeq(this.readSeq(buffer)),
bytes: new Uint8Array(16 + buffer.length)
}

const x = (this.isOutgoing ? 0 : 8) + (this.type === 'Signaling' ? 128 : 0);
const key = this.p2pKey;

// console.log('[encryptor][p2p] encryptPrepared (x, key)', x, key);
const msgKeyLarge = this.concatSHA256([key.subarray(x + 88, x + 88 + 32), buffer]);
const msgKey = result.bytes;
for (let i = 0; i < 16; i++) {
msgKey[i] = msgKeyLarge[i + 8];
}
// console.log('[encryptor][p2p] encryptPrepared msgKeyLarge', msgKeyLarge, msgKey);

// console.log('[encryptor][p2p] encryptPrepared prepareAesKeyIv start', key, msgKey, x);
const aesKeyIv = this.prepareAesKeyIv(key, msgKey, x);
// console.log('[encryptor][p2p] encryptPrepared prepareAesKeyIv stop', aesKeyIv);

// console.log('[encryptor][p2p] encryptPrepared aesProcessCtr start', buffer, buffer.length, aesKeyIv);
const bytes = this.aesProcessCtr(buffer, buffer.length, aesKeyIv, true);
// console.log('[encryptor][p2p] encryptPrepared aesProcessCtr stop', bytes);

result.bytes = new Uint8Array([...result.bytes.subarray(0, 16), ...bytes]);

return result;
}

encryptObjToBase64(obj) {
const str = JSON.stringify(obj);

const enc = new TextEncoder();
const arr = enc.encode(str);

const packet = this.encryptRawPacket(new Uint8Array(arr));

const { bytes } = packet;
const wa = uint8ArrayToWordArray(bytes);

return CryptoJS.enc.Base64.stringify(wa);
}

encryptRawPacket(buffer) {
const seq = ++this.counter;
const arr = new ArrayBuffer(4);
const view = new DataView(arr);
view.setUint32(0, seq >>> 0, false); // byteOffset = 0; litteEndian = false

const result = new Uint8Array([...new Uint8Array(arr), ...buffer]);

// console.log('[encryptor][p2p] encryptRawPacker buffer', result);
const encryptedPacket = this.encryptPrepared(result);

return encryptedPacket;
}

prepareAesKeyIv(key, msgKey, x) {
const sha256a = this.concatSHA256([
msgKey.subarray(0, 16),
key.subarray(x, x + 36)
]);

const sha256b = this.concatSHA256([
key.subarray(40 + x, 40 + x + 36),
msgKey.subarray(0, 16)
]);

return {
key: new Uint8Array([
...sha256a.subarray(0, 8),
...sha256b.subarray(8, 8 + 16),
...sha256a.subarray(24, 24 + 8)
]),
iv: new Uint8Array([
...sha256b.subarray(0, 4),
...sha256a.subarray(8, 8 + 8),
...sha256b.subarray(24, 24 + 4)
])
};
}

const decrypted = CryptoJS.AES.decrypt(base64, key, {
mode,
aesProcessCtr(encryptedData, dataSize, aesKeyIv, encrypt = true) {
const key = uint8ArrayToWordArray(aesKeyIv.key);
const iv = uint8ArrayToWordArray(aesKeyIv.iv);

const str = uint8ArrayToWordArray(encryptedData);
// console.log('[encryptor][p2p] aesProcessCtr (aesKey, aesIv, encrypt)', { key, iv, encrypt, encryptedData });

if (encrypt) {
const encrypted = CryptoJS.AES.encrypt(str, key, {
mode: CryptoJS.mode.CTR,
iv,
padding
padding: CryptoJS.pad.ZeroPadding
});

return decrypted.toString(CryptoJS.enc.Utf8);
const result = wordArrayToUint8Array(encrypted.ciphertext);

// console.log('[encryptor][p2p] aesProcessCtr (result)', { result, ciphertext: encrypted.ciphertext });

return result;
} else {
// from base64 string
return atob(base64);
const decrypted = CryptoJS.AES.decrypt({ ciphertext: str }, key, {
mode: CryptoJS.mode.CTR,
iv,
padding: CryptoJS.pad.ZeroPadding
});

const result = wordArrayToUint8Array(decrypted);

// console.log('[encryptor][p2p] aesProcessCtr (result)', { result, text: decrypted });
return result;
}
}

decryptObjFromBase64(base64) {
const wa = CryptoJS.enc.Base64.parse(base64);

const buffer = wordArrayToUint8Array(wa);
const decrypted = this.decryptRawPacket(buffer);

const dec = new TextDecoder('utf-8');
return JSON.parse(dec.decode(decrypted))
}

decryptRawPacket(buffer) {
if (buffer.length < 21 || buffer.length > kMaxIncomingPacketSize) {
return null;
}

const { isOutgoing, type } = this;

const x = (isOutgoing ? 8 : 0) + (type === 'Signaling' ? 128 : 0);
const key = this.p2pKey;
// console.log('[encryptor][p2p] decryptRawPacket (x, key)', x, key);

const msgKey = buffer.subarray(0, 16);
const encryptedData = buffer.subarray(16);
const encryptedDataSize = buffer.length - 16;

// console.log('[encryptor][p2p] decryptRawPacket prepareAesKeyIv start', { key, msgKey, x });
const aesKeyIv = this.prepareAesKeyIv(key, msgKey, x);
// console.log('[encryptor][p2p] decryptRawPacket prepareAesKeyIv stop', aesKeyIv);

// console.log('[encryptor][p2p] decryptRawPacket aesProcessCtr start', encryptedData, dataSize, aesKeyIv);
const decryptionBuffer = this.aesProcessCtr(encryptedData, encryptedDataSize, aesKeyIv, false);
// console.log('[encryptor][p2p] decryptRawPacket aesProcessCtr stop', decryptionBuffer);

const msgKeyLarge = this.concatSHA256([
key.subarray(88 + x, 88 + x + 32),
decryptionBuffer
]);

let msgKeyEquals = true;
for (let i = 0; i < 16; i++) {
if (msgKey[i] !== msgKeyLarge[i + 8]) {
msgKeyEquals = false;
}
}
console.log('[msgKey]', msgKey, msgKeyLarge, msgKeyEquals);
if (!msgKeyEquals) {
return null;
}

const resultBuffer = decryptionBuffer.slice(4);

return resultBuffer;
}
};
7 changes: 4 additions & 3 deletions src/Stores/CallStore.js
View file
Expand Up @@ -249,16 +249,17 @@ class CallStore extends EventEmitter {
const { encryptor } = currentCall;
if (encryptor) {
const decryptedData = encryptor.decryptFromBase64(data);
LOG_P2P_CALL('[update] updateNewCallSignalingData', update, decryptedData);
const signalingData = JSON.parse(decryptedData);
// LOG_P2P_CALL('[update] updateNewCallSignalingData', update, signalingData);
// const signalingData = JSON.parse(atob(data));
LOG_P2P_CALL('[update] updateNewCallSignalingData', update, signalingData);
if (this.p2pCallsEnabled) {
this.p2pApplyCallSignalingData(call_id, signalingData);
}
}
}
} catch (e) {
ERROR_P2P_CALL('[update] updateNewSignalingData parse', update);
ERROR_P2P_CALL('[update] updateNewSignalingData parse', update, e);
}

this.emit('updateNewCallSignalingData', update);
Expand Down Expand Up @@ -1803,7 +1804,7 @@ class CallStore extends EventEmitter {
connection,
inputStream: null,
outputStream,
encryptor: new P2PEncryptor(encryption_key)
encryptor: new P2PEncryptor(is_outgoing, encryption_key)
};
LOG_P2P_CALL('p2pJoinCall currentCall', this.currentCall);

Expand Down

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