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fix(websocket): run parser in loop, instead of recursively #1828

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Dec 22, 2022
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fix(websocket): run parser in loop, instead of recursively #1828

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309 changes: 156 additions & 153 deletions lib/websocket/receiver.js
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Original file line number Diff line number Diff line change
Expand Up @@ -48,201 +48,204 @@ class ByteParser extends Writable {
* or not enough bytes are buffered to parse.
*/
run (callback) {
if (this.#state === parserStates.INFO) {
// If there aren't enough bytes to parse the payload length, etc.
if (this.#byteOffset < 2) {
return callback()
}
while (true) {
if (this.#state === parserStates.INFO) {
// If there aren't enough bytes to parse the payload length, etc.
if (this.#byteOffset < 2) {
return callback()
}

const buffer = this.consume(2)
const buffer = this.consume(2)

this.#info.fin = (buffer[0] & 0x80) !== 0
this.#info.opcode = buffer[0] & 0x0F
this.#info.fin = (buffer[0] & 0x80) !== 0
this.#info.opcode = buffer[0] & 0x0F

// If we receive a fragmented message, we use the type of the first
// frame to parse the full message as binary/text, when it's terminated
this.#info.originalOpcode ??= this.#info.opcode
// If we receive a fragmented message, we use the type of the first
// frame to parse the full message as binary/text, when it's terminated
this.#info.originalOpcode ??= this.#info.opcode

this.#info.fragmented = !this.#info.fin && this.#info.opcode !== opcodes.CONTINUATION
this.#info.fragmented = !this.#info.fin && this.#info.opcode !== opcodes.CONTINUATION

if (this.#info.fragmented && this.#info.opcode !== opcodes.BINARY && this.#info.opcode !== opcodes.TEXT) {
// Only text and binary frames can be fragmented
failWebsocketConnection(this.ws, 'Invalid frame type was fragmented.')
return
}
if (this.#info.fragmented && this.#info.opcode !== opcodes.BINARY && this.#info.opcode !== opcodes.TEXT) {
// Only text and binary frames can be fragmented
failWebsocketConnection(this.ws, 'Invalid frame type was fragmented.')
return
}

const payloadLength = buffer[1] & 0x7F
const payloadLength = buffer[1] & 0x7F

if (payloadLength <= 125) {
this.#info.payloadLength = payloadLength
this.#state = parserStates.READ_DATA
} else if (payloadLength === 126) {
this.#state = parserStates.PAYLOADLENGTH_16
} else if (payloadLength === 127) {
this.#state = parserStates.PAYLOADLENGTH_64
}
if (payloadLength <= 125) {
this.#info.payloadLength = payloadLength
this.#state = parserStates.READ_DATA
} else if (payloadLength === 126) {
this.#state = parserStates.PAYLOADLENGTH_16
} else if (payloadLength === 127) {
this.#state = parserStates.PAYLOADLENGTH_64
}

if (this.#info.fragmented && payloadLength > 125) {
// A fragmented frame can't be fragmented itself
failWebsocketConnection(this.ws, 'Fragmented frame exceeded 125 bytes.')
return
} else if (
(this.#info.opcode === opcodes.PING ||
this.#info.opcode === opcodes.PONG ||
this.#info.opcode === opcodes.CLOSE) &&
payloadLength > 125
) {
// Control frames can have a payload length of 125 bytes MAX
failWebsocketConnection(this.ws, 'Payload length for control frame exceeded 125 bytes.')
return
} else if (this.#info.opcode === opcodes.CLOSE) {
if (payloadLength === 1) {
failWebsocketConnection(this.ws, 'Received close frame with a 1-byte body.')
if (this.#info.fragmented && payloadLength > 125) {
// A fragmented frame can't be fragmented itself
failWebsocketConnection(this.ws, 'Fragmented frame exceeded 125 bytes.')
return
}
} else if (
(this.#info.opcode === opcodes.PING ||
this.#info.opcode === opcodes.PONG ||
this.#info.opcode === opcodes.CLOSE) &&
payloadLength > 125
) {
// Control frames can have a payload length of 125 bytes MAX
failWebsocketConnection(this.ws, 'Payload length for control frame exceeded 125 bytes.')
return
} else if (this.#info.opcode === opcodes.CLOSE) {
if (payloadLength === 1) {
failWebsocketConnection(this.ws, 'Received close frame with a 1-byte body.')
return
}

const body = this.consume(payloadLength)
const body = this.consume(payloadLength)

this.#info.closeInfo = this.parseCloseBody(false, body)

if (!this.ws[kSentClose]) {
// If an endpoint receives a Close frame and did not previously send a
// Close frame, the endpoint MUST send a Close frame in response. (When
// sending a Close frame in response, the endpoint typically echos the
// status code it received.)
const body = Buffer.allocUnsafe(2)
body.writeUInt16BE(this.#info.closeInfo.code, 0)
const closeFrame = new WebsocketFrameSend(body)

this.ws[kResponse].socket.write(
closeFrame.createFrame(opcodes.CLOSE),
(err) => {
if (!err) {
this.ws[kSentClose] = true
}
}
)
}

this.#info.closeInfo = this.parseCloseBody(false, body)
// Upon either sending or receiving a Close control frame, it is said
// that _The WebSocket Closing Handshake is Started_ and that the
// WebSocket connection is in the CLOSING state.
this.ws[kReadyState] = states.CLOSING
this.ws[kReceivedClose] = true

if (!this.ws[kSentClose]) {
// If an endpoint receives a Close frame and did not previously send a
// Close frame, the endpoint MUST send a Close frame in response. (When
// sending a Close frame in response, the endpoint typically echos the
// status code it received.)
const body = Buffer.allocUnsafe(2)
body.writeUInt16BE(this.#info.closeInfo.code, 0)
const closeFrame = new WebsocketFrameSend(body)
this.end()

this.ws[kResponse].socket.write(
closeFrame.createFrame(opcodes.CLOSE),
(err) => {
if (!err) {
this.ws[kSentClose] = true
}
}
)
}
return
} else if (this.#info.opcode === opcodes.PING) {
// Upon receipt of a Ping frame, an endpoint MUST send a Pong frame in
// response, unless it already received a Close frame.
// A Pong frame sent in response to a Ping frame must have identical
// "Application data"

const body = this.consume(payloadLength)

// Upon either sending or receiving a Close control frame, it is said
// that _The WebSocket Closing Handshake is Started_ and that the
// WebSocket connection is in the CLOSING state.
this.ws[kReadyState] = states.CLOSING
this.ws[kReceivedClose] = true
if (!this.ws[kReceivedClose]) {
const frame = new WebsocketFrameSend(body)

this.end()
this.ws[kResponse].socket.write(frame.createFrame(opcodes.PONG))

return
} else if (this.#info.opcode === opcodes.PING) {
// Upon receipt of a Ping frame, an endpoint MUST send a Pong frame in
// response, unless it already received a Close frame.
// A Pong frame sent in response to a Ping frame must have identical
// "Application data"
if (channels.ping.hasSubscribers) {
channels.ping.publish({
payload: body
})
}
}

const body = this.consume(payloadLength)
this.#state = parserStates.INFO

if (!this.ws[kReceivedClose]) {
const frame = new WebsocketFrameSend(body)
if (this.#byteOffset > 0) {
continue
} else {
callback()
return
}
} else if (this.#info.opcode === opcodes.PONG) {
// A Pong frame MAY be sent unsolicited. This serves as a
// unidirectional heartbeat. A response to an unsolicited Pong frame is
// not expected.

this.ws[kResponse].socket.write(frame.createFrame(opcodes.PONG))
const body = this.consume(payloadLength)

if (channels.ping.hasSubscribers) {
channels.ping.publish({
if (channels.pong.hasSubscribers) {
channels.pong.publish({
payload: body
})
}
}

this.#state = parserStates.INFO

if (this.#byteOffset > 0) {
return this.run(callback)
} else {
callback()
return
if (this.#byteOffset > 0) {
continue
} else {
callback()
return
}
}
} else if (this.#state === parserStates.PAYLOADLENGTH_16) {
if (this.#byteOffset < 2) {
return callback()
}
} else if (this.#info.opcode === opcodes.PONG) {
// A Pong frame MAY be sent unsolicited. This serves as a
// unidirectional heartbeat. A response to an unsolicited Pong frame is
// not expected.

const body = this.consume(payloadLength)
const buffer = this.consume(2)

if (channels.pong.hasSubscribers) {
channels.pong.publish({
payload: body
})
this.#info.payloadLength = buffer.readUInt16BE(0)
this.#state = parserStates.READ_DATA
} else if (this.#state === parserStates.PAYLOADLENGTH_64) {
if (this.#byteOffset < 8) {
return callback()
}

if (this.#byteOffset > 0) {
return this.run(callback)
} else {
callback()
const buffer = this.consume(8)
const upper = buffer.readUInt32BE(0)

// 2^31 is the maxinimum bytes an arraybuffer can contain
// on 32-bit systems. Although, on 64-bit systems, this is
// 2^53-1 bytes.
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Errors/Invalid_array_length
// https://source.chromium.org/chromium/chromium/src/+/main:v8/src/common/globals.h;drc=1946212ac0100668f14eb9e2843bdd846e510a1e;bpv=1;bpt=1;l=1275
// https://source.chromium.org/chromium/chromium/src/+/main:v8/src/objects/js-array-buffer.h;l=34;drc=1946212ac0100668f14eb9e2843bdd846e510a1e
if (upper > 2 ** 31 - 1) {
failWebsocketConnection(this.ws, 'Received payload length > 2^31 bytes.')
return
}
}
} else if (this.#state === parserStates.PAYLOADLENGTH_16) {
if (this.#byteOffset < 2) {
return callback()
}

const buffer = this.consume(2)

this.#info.payloadLength = buffer.readUInt16BE(0)
this.#state = parserStates.READ_DATA
} else if (this.#state === parserStates.PAYLOADLENGTH_64) {
if (this.#byteOffset < 8) {
return callback()
}

const buffer = this.consume(8)
const upper = buffer.readUInt32BE(0)

// 2^31 is the maxinimum bytes an arraybuffer can contain
// on 32-bit systems. Although, on 64-bit systems, this is
// 2^53-1 bytes.
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Errors/Invalid_array_length
// https://source.chromium.org/chromium/chromium/src/+/main:v8/src/common/globals.h;drc=1946212ac0100668f14eb9e2843bdd846e510a1e;bpv=1;bpt=1;l=1275
// https://source.chromium.org/chromium/chromium/src/+/main:v8/src/objects/js-array-buffer.h;l=34;drc=1946212ac0100668f14eb9e2843bdd846e510a1e
if (upper > 2 ** 31 - 1) {
failWebsocketConnection(this.ws, 'Received payload length > 2^31 bytes.')
return
}
const lower = buffer.readUInt32BE(4)

const lower = buffer.readUInt32BE(4)
this.#info.payloadLength = (upper << 8) + lower
this.#state = parserStates.READ_DATA
} else if (this.#state === parserStates.READ_DATA) {
if (this.#byteOffset < this.#info.payloadLength) {
// If there is still more data in this chunk that needs to be read
return callback()
} else if (this.#byteOffset >= this.#info.payloadLength) {
// If the server sent multiple frames in a single chunk

this.#info.payloadLength = (upper << 8) + lower
this.#state = parserStates.READ_DATA
} else if (this.#state === parserStates.READ_DATA) {
if (this.#byteOffset < this.#info.payloadLength) {
// If there is still more data in this chunk that needs to be read
return callback()
} else if (this.#byteOffset >= this.#info.payloadLength) {
// If the server sent multiple frames in a single chunk
const body = this.consume(this.#info.payloadLength)

const body = this.consume(this.#info.payloadLength)
this.#fragments.push(body)

this.#fragments.push(body)
// If the frame is unfragmented, or a fragmented frame was terminated,
// a message was received
if (!this.#info.fragmented || (this.#info.fin && this.#info.opcode === opcodes.CONTINUATION)) {
const fullMessage = Buffer.concat(this.#fragments)

// If the frame is unfragmented, or a fragmented frame was terminated,
// a message was received
if (!this.#info.fragmented || (this.#info.fin && this.#info.opcode === opcodes.CONTINUATION)) {
const fullMessage = Buffer.concat(this.#fragments)
websocketMessageReceived(this.ws, this.#info.originalOpcode, fullMessage)

websocketMessageReceived(this.ws, this.#info.originalOpcode, fullMessage)
this.#info = {}
this.#fragments.length = 0
}

this.#info = {}
this.#fragments.length = 0
this.#state = parserStates.INFO
}

this.#state = parserStates.INFO
}
}

if (this.#byteOffset > 0) {
return this.run(callback)
} else {
callback()
if (this.#byteOffset > 0) {
continue
} else {
callback()
break
}
}
}

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