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refactor: use @projectdysnomia/libsodium to perform voice encryption #179

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refactor: use @projectdysnomia/libsodium to perform voice encryption #179

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c70263a
make stablelib a peer dependency
TTtie Nov 2, 2024
6f3f6c6
refactor: use @projectdysnomia/libsodium to perform packet encryption
TTtie Nov 2, 2024
da6fc58
free the nonce buffer after decryption
TTtie Nov 2, 2024
22bceec
make VoiceConnection##alloc more clear
TTtie Nov 2, 2024
df12822
pass a buffer to the stablelib constructor, not a buffer pointer
TTtie Nov 2, 2024
cc039c1
style: merge if tree into ternary
TTtie Nov 2, 2024
910fd3a
free the sendBuffer and sendHeader when destroying the voice connecti…
TTtie Nov 2, 2024
5286313
free the nonce buffer and the secret buffer after disconnecting
TTtie Nov 2, 2024
ca5c0c1
this is probably meant to be the length of the buffer
TTtie Aug 23, 2026
e0df05f
chore: regenerate package lock
TTtie Aug 25, 2026
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124 changes: 89 additions & 35 deletions lib/voice/VoiceConnection.js
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Original file line number Diff line number Diff line change
Expand Up @@ -21,8 +21,11 @@ try {

/** @type {import("@snazzah/davey")?} */
let Davey = null;
/** @type {import("@stablelib/xchacha20poly1305")?} */
let StableLib = null;
/** @type {import("@projectdysnomia/libsodium")?} */
let Sodium = null;
/** @type {import("node:crypto")?} */
let crypto = null;
let aes256Available = false;

Expand Down Expand Up @@ -107,8 +110,6 @@ class VoiceConnection extends EventEmitter {
reconnecting = false;
reinitializing = false;
samplingRate = 48_000;
sendBuffer = Buffer.allocUnsafe(16 + 32 + MAX_FRAME_SIZE);
sendHeader = Buffer.alloc(12);
sequence = 0;
speaking = false;
ssrcUserMap = {};
Expand All @@ -119,8 +120,10 @@ class VoiceConnection extends EventEmitter {
#daveDowngraded = false;
#davePendingTransitions = new Map();
#nonce = 0;
/** @type {import("@projectdysnomia/libsodium").BufferPointer?} */
#nonceBuffer = null;
#send;
/** @type {import("@stablelib/xchacha20poly1305").XChaCha20Poly1305?} */
#stablelib = null;
/** @type {String?} */
#userID = null;
Expand All @@ -142,7 +145,7 @@ class VoiceConnection extends EventEmitter {

if(!Sodium && !StableLib) {
try {
Sodium = require("sodium-native");
Sodium = require("@projectdysnomia/libsodium");
} catch {
try {
StableLib = require("@stablelib/xchacha20poly1305");
Expand Down Expand Up @@ -187,6 +190,9 @@ class VoiceConnection extends EventEmitter {
this.opus = {};
}

this.sendBuffer = this.#alloc(16 + 32 + MAX_FRAME_SIZE, false);
this.sendHeader = this.#alloc(12);

this.sendHeader[0] = 0x80;
this.sendHeader[1] = 0x78;

Expand Down Expand Up @@ -461,10 +467,10 @@ class VoiceConnection extends EventEmitter {
}
case VoiceOPCodes.SESSION_DESCRIPTION: {
this.mode = packet.d.mode;
this.secret = Buffer.from(packet.d.secret_key);
this.#nonceBuffer = Buffer.alloc(this.mode === "aead_aes256_gcm_rtpsize" ? 12 : 24);
this.secret = this.#transfer(Buffer.from(packet.d.secret_key));
this.#nonceBuffer = this.#alloc(this.mode === "aead_aes256_gcm_rtpsize" ? 12 : 24);
if(this.mode === "aead_xchacha20_poly1305_rtpsize" && StableLib) {
this.#stablelib = new StableLib.XChaCha20Poly1305(this.secret);
this.#stablelib = new StableLib.XChaCha20Poly1305(this.secret.buffer);
}
this.daveProtocolVersion = packet.d.dave_protocol_version;
this.connecting = false;
Expand Down Expand Up @@ -688,6 +694,10 @@ class VoiceConnection extends EventEmitter {
this.sessionID = null;
this.token = null;
this.wsSequence = -1;
this.secret?.free();
this.#nonceBuffer?.free();
this.secret = null;
this.#nonceBuffer = null;
this.#stablelib = null;
this.updateVoiceState();
/**
Expand Down Expand Up @@ -869,8 +879,8 @@ class VoiceConnection extends EventEmitter {
const hasExtension = !!(msg[0] & 0b10000);
const hasPadding = !!(msg[0] & 0b100000);
const cc = msg[0] & 0b1111;
const nonce = Buffer.alloc(this.mode === "aead_aes256_gcm_rtpsize" ? 12 : 24);
msg.copy(nonce, 0, msg.length - 4, msg.length);
const nonce = this.#alloc(this.mode === "aead_aes256_gcm_rtpsize" ? 12 : 24);
msg.copy(nonce.buffer, 0, msg.length - 4, msg.length);

// Header Size = Fixed Header Length + (CSRC Identifier Length * CSRC count) + Extension
let headerSize = 12 + (cc * 4);
Expand All @@ -880,23 +890,30 @@ class VoiceConnection extends EventEmitter {

let data;
if(this.mode === "aead_aes256_gcm_rtpsize") {
const decipher = crypto.createDecipheriv("aes-256-gcm", this.secret, nonce);
const decipher = crypto.createDecipheriv("aes-256-gcm", this.secret.buffer, nonce.buffer);
decipher.setAAD(msg.subarray(0, headerSize));
decipher.setAuthTag(msg.subarray(msg.length - 20, msg.length - 4));
data = Buffer.concat([decipher.update(msg.subarray(headerSize, msg.length - 20)), decipher.final()]);
} else if(Sodium) {
data = Buffer.alloc(msg.length - (headerSize + 4) - Sodium.crypto_aead_xchacha20poly1305_ietf_ABYTES);
const msgPtr = this.#transfer(msg);
const d = this.#alloc(msg.length - (headerSize + 4) - Sodium.crypto_aead_xchacha20poly1305_ietf_ABYTES);
Sodium.crypto_aead_xchacha20poly1305_ietf_decrypt(
data,
d,
null,
msg.subarray(headerSize, msg.length - 4),
msg.subarray(0, headerSize),
msgPtr.subarray(headerSize, msg.length - 4),
msgPtr.subarray(0, headerSize),
nonce,
this.secret
);

// SAFE: the native backend has no concept of freeing memory, so the buffer can be used directly
data = Sodium.native ? d.buffer : Buffer.from(d.buffer);

msgPtr.free();
d.free();
} else if(this.#stablelib) {
data = this.#stablelib.open(
nonce,
nonce.buffer,
msg.subarray(headerSize, msg.length - 4),
msg.subarray(0, headerSize)
);
Expand All @@ -907,6 +924,8 @@ class VoiceConnection extends EventEmitter {
data = Buffer.from(data.buffer);
}

nonce.free();

// RFC3550 5.1: Padding (may need testing)
if(hasPadding) {
const paddingAmount = data[data.length - 1];
Expand Down Expand Up @@ -1137,6 +1156,8 @@ class VoiceConnection extends EventEmitter {
}

_destroy() {
this.sendBuffer.free();
this.sendHeader.free();
if(this.opus) {
for(const key in this.opus) {
this.opus[key].delete?.();
Expand All @@ -1155,28 +1176,28 @@ class VoiceConnection extends EventEmitter {
}

_sendAudioFrame(unencryptedFrame) {
const headerSize = this.sendHeader.length;
this.sendHeader.writeUInt16BE(this.sequence, 2);
this.sendHeader.writeUInt32BE(this.timestamp, 4);
const headerSize = this.sendHeader.buffer.length;
this.sendHeader.buffer.writeUInt16BE(this.sequence, 2);
this.sendHeader.buffer.writeUInt32BE(this.timestamp, 4);

this.#nonce = (this.#nonce + 1) >>> 0;
this.#nonceBuffer.writeUInt32BE(this.#nonce, 0);
this.#nonceBuffer.buffer.writeUInt32BE(this.#nonce, 0);

const frame = this.#daveReady && !unencryptedFrame.equals(SILENCE_FRAME) ? this.daveSession.encryptOpus(unencryptedFrame) : unencryptedFrame;

if(this.mode === "aead_aes256_gcm_rtpsize") {
const cipher = crypto.createCipheriv("aes-256-gcm", this.secret, this.#nonceBuffer);
cipher.setAAD(this.sendHeader);
const cipher = crypto.createCipheriv("aes-256-gcm", this.secret.buffer, this.#nonceBuffer.buffer);
cipher.setAAD(this.sendHeader.buffer);
const result = Buffer.concat([cipher.update(frame), cipher.final(), cipher.getAuthTag()]);
this.sendHeader.copy(this.sendBuffer, 0, 0, headerSize);
result.copy(this.sendBuffer, headerSize);
this.#nonceBuffer.copy(this.sendBuffer, headerSize + result.length, 0, 4); // nonce padding
return this.sendUDPPacket(this.sendBuffer.subarray(0, headerSize + result.length + 4));
this.sendHeader.buffer.copy(this.sendBuffer.buffer, 0, 0, headerSize);
result.copy(this.sendBuffer.buffer, headerSize);
this.#nonceBuffer.buffer.copy(this.sendBuffer.buffer, headerSize + result.length, 0, 4); // nonce padding
return this.sendUDPPacket(this.sendBuffer.subarray(0, headerSize + result.length + 4).buffer);
} else if(Sodium) {
const ABYTES = Sodium.crypto_aead_xchacha20poly1305_ietf_ABYTES;
const length = frame.length + ABYTES;
this.sendBuffer.fill(0, headerSize + frame.length, headerSize + frame.length + ABYTES);
frame.copy(this.sendBuffer, headerSize);
this.sendBuffer.buffer.fill(0, headerSize + frame.length, headerSize + frame.length + ABYTES);
frame.copy(this.sendBuffer.buffer, headerSize);
Sodium.crypto_aead_xchacha20poly1305_ietf_encrypt(
this.sendBuffer.subarray(headerSize, headerSize + length),
this.sendBuffer.subarray(headerSize, headerSize + frame.length),
Expand All @@ -1185,21 +1206,33 @@ class VoiceConnection extends EventEmitter {
this.#nonceBuffer,
this.secret
);
this.sendHeader.copy(this.sendBuffer, 0, 0, headerSize);
this.#nonceBuffer.copy(this.sendBuffer, headerSize + length, 0, 4); // nonce padding
return this.sendUDPPacket(this.sendBuffer.subarray(0, headerSize + length + 4));
this.sendHeader.buffer.copy(this.sendBuffer, 0, 0, headerSize);
this.#nonceBuffer.buffer.copy(this.sendBuffer, headerSize + length, 0, 4); // nonce padding
return this.sendUDPPacket(this.sendBuffer.subarray(0, headerSize + length + 4).buffer);
} else if(this.#stablelib) {
const length = frame.length + StableLib.TAG_LENGTH;
this.sendBuffer.fill(0, headerSize + frame.length, headerSize + length);
this.#stablelib.seal(
this.#nonceBuffer,
this.#nonceBuffer.buffer,
frame,
this.sendHeader,
this.sendBuffer.subarray(headerSize, headerSize + length)
this.sendHeader.buffer,
this.sendBuffer.subarray(headerSize, headerSize + length).buffer
);
this.sendHeader.copy(this.sendBuffer, 0, 0, headerSize);
this.#nonceBuffer.copy(this.sendBuffer, headerSize + length, 0, 4); // nonce padding
return this.sendUDPPacket(this.sendBuffer.subarray(0, headerSize + length + 4));
this.sendHeader.buffer.copy(this.sendBuffer.buffer, 0, 0, headerSize);
this.#nonceBuffer.buffer.copy(this.sendBuffer.buffer, headerSize + length, 0, 4); // nonce padding
return this.sendUDPPacket(this.sendBuffer.subarray(0, headerSize + length + 4).buffer);
}
}

/**
* @param {Number} size
* @param {Boolean} zero
*/
#alloc(size, zero = true) {
if(Sodium) {
return Sodium.alloc(size, zero);
} else {
return this.#makeBufferPointer(zero ? Buffer.alloc(size) : Buffer.allocUnsafe(size));
}
}

Expand Down Expand Up @@ -1247,6 +1280,18 @@ class VoiceConnection extends EventEmitter {
return true;
}

/** @param {Buffer} buf */
#makeBufferPointer(buf) {
// Keep in sync with BufferPointer in @projectdysnomia/libsodium to maintain compatibility
return {
buffer: buf,
free: () => {},
subarray: (start, end) => {
return this.#makeBufferPointer(buf.subarray(start, end));
}
};
}

#reinitDaveSession(userID, channelID) {
if(this.daveProtocolVersion > 0) {
if(this.daveSession) {
Expand Down Expand Up @@ -1297,6 +1342,15 @@ class VoiceConnection extends EventEmitter {
this.current.timeout = setTimeout(this.#send, this.current.startTime + this.current.pausedTime + this.current.playTime - Date.now());
}

/** @param {Buffer} buf */
#transfer(buf) {
if(Sodium) {
return Sodium.transfer(buf);
} else {
return this.#makeBufferPointer(buf);
}
}

[util.inspect.custom]() {
return Base.prototype[util.inspect.custom].call(this);
}
Expand Down
6 changes: 5 additions & 1 deletion package.json
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Original file line number Diff line number Diff line change
Expand Up @@ -56,7 +56,7 @@
},
"optionalDependencies": {
"@snazzah/davey": "^0.1.12",
"@stablelib/xchacha20poly1305": "~1.0.1",
"@projectdysnomia/libsodium": "github:projectdysnomia/libsodium#acefd1b44526953eed4f0a87e31149963d052d21",
"opusscript": "^0.1.1"
},
"browser": {
Expand All @@ -70,6 +70,7 @@
},
"peerDependencies": {
"@discordjs/opus": "^0.10.0",
"@stablelib/xchacha20poly1305": "~1.0.1",
"erlpack": "github:discord/erlpack",
"eventemitter3": "^5.0.1",
"pako": "^2.1.0",
Expand All @@ -80,6 +81,9 @@
"@discordjs/opus": {
"optional": true
},
"@stablelib/xchacha20poly1305": {
"optional": true
},
"eventemitter3": {
"optional": true
},
Expand Down
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