feat: add configurable maxPayloadSize for WebSocket

docs/docs/api/Client.md

@@ -24,6 +24,8 @@ Returns: `Client`
 * **keepAliveTimeoutThreshold** `number | null` (optional) - Default: `2e3` - A number of milliseconds subtracted from server *keep-alive* hints when overriding `keepAliveTimeout` to account for timing inaccuracies caused by e.g. transport latency. Defaults to 2 seconds.
 * **maxHeaderSize** `number | null` (optional) - Default: `--max-http-header-size` or `16384` - The maximum length of request headers in bytes. Defaults to Node.js' --max-http-header-size or 16KiB.
 * **maxResponseSize** `number | null` (optional) - Default: `-1` - The maximum length of response body in bytes. Set to `-1` to disable.
+* **webSocket** `WebSocketOptions` (optional) - WebSocket-specific configuration options.
+  * **maxPayloadSize** `number` (optional) - Default: `134217728` (128 MB) - Maximum allowed payload size in bytes for WebSocket messages. Applied to both uncompressed and decompressed (permessage-deflate) messages. For decompressed messages, uses a conservative 10x expansion ratio estimate for early rejection. Set to 0 to disable the limit.
 * **pipelining** `number | null` (optional) - Default: `1` - The amount of concurrent requests to be sent over the single TCP/TLS connection according to [RFC7230](https://tools.ietf.org/html/rfc7230#section-6.3.2). Carefully consider your workload and environment before enabling concurrent requests as pipelining may reduce performance if used incorrectly. Pipelining is sensitive to network stack settings as well as head of line blocking caused by e.g. long running requests. Set to `0` to disable keep-alive connections.
 * **connect** `ConnectOptions | Function | null` (optional) - Default: `null`.
 * **strictContentLength** `Boolean` (optional) - Default: `true` - Whether to treat request content length mismatches as errors. If true, an error is thrown when the request content-length header doesn't match the length of the request body. **Security Warning:** Disabling this option can expose your application to HTTP Request Smuggling attacks, where mismatched content-length headers cause servers and proxies to interpret request boundaries differently. This can lead to cache poisoning, credential hijacking, and bypassing security controls. Only disable this in controlled environments where you fully trust the request source.

lib/dispatcher/agent.js

@@ -35,7 +35,7 @@ class Agent extends DispatcherBase {
       throw new InvalidArgumentError('maxOrigins must be a number greater than 0')
     }
 
-    super()
+    super(options)
 
     if (connect && typeof connect !== 'function') {
       connect = { ...connect }

lib/dispatcher/client.js

@@ -114,7 +114,8 @@ class Client extends DispatcherBase {
     useH2c,
     initialWindowSize,
     connectionWindowSize,
-    pingInterval
+    pingInterval,
+    webSocket
   } = {}) {
     if (keepAlive !== undefined) {
       throw new InvalidArgumentError('unsupported keepAlive, use pipelining=0 instead')
@@ -222,7 +223,7 @@ class Client extends DispatcherBase {
       throw new InvalidArgumentError('pingInterval must be a positive integer, greater or equal to 0')
     }
 
-    super()
+    super({ webSocket })
 
     if (typeof connect !== 'function') {
       connect = buildConnector({

lib/dispatcher/dispatcher-base.js

@@ -11,6 +11,7 @@ const { kDestroy, kClose, kClosed, kDestroyed, kDispatch } = require('../core/sy
 
 const kOnDestroyed = Symbol('onDestroyed')
 const kOnClosed = Symbol('onClosed')
+const kWebSocketOptions = Symbol('webSocketOptions')
 
 class DispatcherBase extends Dispatcher {
   /** @type {boolean} */
@@ -25,6 +26,23 @@ class DispatcherBase extends Dispatcher {
   /** @type {Array<Function>|null} */
   [kOnClosed] = null
 
+  /**
+   * @param {import('../../types/dispatcher').DispatcherOptions} [opts]
+   */
+  constructor (opts) {
+    super()
+    this[kWebSocketOptions] = opts?.webSocket ?? {}
+  }
+
+  /**
+   * @returns {import('../../types/dispatcher').WebSocketOptions}
+   */
+  get webSocketOptions () {
+    return {
+      maxPayloadSize: this[kWebSocketOptions].maxPayloadSize ?? 128 * 1024 * 1024 // 128 MB default
+    }
+  }
+
   /** @returns {boolean} */
   get destroyed () {
     return this[kDestroyed]

lib/dispatcher/pool.js

@@ -63,7 +63,7 @@ class Pool extends PoolBase {
       })
     }
 
-    super()
+    super(options)
 
     this[kConnections] = connections || null
     this[kUrl] = util.parseOrigin(origin)

lib/web/websocket/permessage-deflate.js

@@ -8,15 +8,20 @@ const tail = Buffer.from([0x00, 0x00, 0xff, 0xff])
 const kBuffer = Symbol('kBuffer')
 const kLength = Symbol('kLength')
 
-// Default maximum decompressed message size: 4 MB
-const kDefaultMaxDecompressedSize = 4 * 1024 * 1024
+// Default maximum decompressed message size: 128 MB
+const kDefaultMaxDecompressedSize = 128 * 1024 * 1024
+// Maximum expansion ratio for estimated size check (conservative DEFLATE upper bound)
+const kMaxExpansionRatio = 10
 
 class PerMessageDeflate {
   /** @type {import('node:zlib').InflateRaw} */
   #inflate
 
   #options = {}
 
+  /** @type {number} */
+  #maxDecompressedSize
+
   /** @type {boolean} */
   #aborted = false
 
@@ -25,18 +30,46 @@ class PerMessageDeflate {
 
   /**
    * @param {Map<string, string>} extensions
+   * @param {{ maxPayloadSize?: number }} [options]
    */
-  constructor (extensions) {
+  constructor (extensions, options = {}) {
     this.#options.serverNoContextTakeover = extensions.has('server_no_context_takeover')
     this.#options.serverMaxWindowBits = extensions.get('server_max_window_bits')
+    // 0 disables the limit
+    this.#maxDecompressedSize = options.maxPayloadSize ?? kDefaultMaxDecompressedSize
+  }
+
+  /**
+   * Check if compressed payload could exceed the decompressed size limit.
+   * Uses a conservative expansion ratio estimate for early rejection.
+   * @param {number} compressedLength
+   * @returns {boolean} true if the message should be rejected
+   */
+  #exceedsEstimatedLimit (compressedLength) {
+    // 0 disables the limit
+    if (this.#maxDecompressedSize <= 0) return false
+    return compressedLength * kMaxExpansionRatio > this.#maxDecompressedSize
   }
 
-  decompress (chunk, fin, callback) {
+  /**
+   * Decompress a compressed payload.
+   * @param {Buffer} chunk Compressed data
+   * @param {boolean} fin Final fragment flag
+   * @param {Function} callback Callback function
+   * @param {number} [compressedLength] Compressed payload length for estimated size check
+   */
+  decompress (chunk, fin, callback, compressedLength) {
     // An endpoint uses the following algorithm to decompress a message.
     // 1.  Append 4 octets of 0x00 0x00 0xff 0xff to the tail end of the
     //     payload of the message.
     // 2.  Decompress the resulting data using DEFLATE.
 
+    // Early rejection based on estimated expansion
+    if (compressedLength != null && this.#exceedsEstimatedLimit(compressedLength)) {
+      callback(new MessageSizeExceededError())
+      return
+    }
+
     if (this.#aborted) {
       callback(new MessageSizeExceededError())
       return
@@ -70,7 +103,8 @@ class PerMessageDeflate {
 
         this.#inflate[kLength] += data.length
 
-        if (this.#inflate[kLength] > kDefaultMaxDecompressedSize) {
+        // 0 disables the limit
+        if (this.#maxDecompressedSize > 0 && this.#inflate[kLength] > this.#maxDecompressedSize) {
           this.#aborted = true
           this.#inflate.removeAllListeners()
           this.#inflate.destroy()

lib/web/websocket/receiver.js

@@ -39,18 +39,23 @@ class ByteParser extends Writable {
   /** @type {import('./websocket').Handler} */
   #handler
 
+  /** @type {number} */
+  #maxPayloadSize
+
   /**
    * @param {import('./websocket').Handler} handler
    * @param {Map<string, string>|null} extensions
+   * @param {{ maxPayloadSize?: number }} [options]
    */
-  constructor (handler, extensions) {
+  constructor (handler, extensions, options = {}) {
     super()
 
     this.#handler = handler
     this.#extensions = extensions == null ? new Map() : extensions
+    this.#maxPayloadSize = options.maxPayloadSize ?? 0
 
     if (this.#extensions.has('permessage-deflate')) {
-      this.#extensions.set('permessage-deflate', new PerMessageDeflate(extensions))
+      this.#extensions.set('permessage-deflate', new PerMessageDeflate(extensions, options))
     }
   }
 
@@ -66,6 +71,20 @@ class ByteParser extends Writable {
     this.run(callback)
   }
 
+  #validatePayloadLength () {
+    if (
+      this.#maxPayloadSize > 0 &&
+      !isControlFrame(this.#info.opcode) &&
+      !this.#info.compressed &&
+      this.#fragmentsBytes + this.#info.payloadLength > this.#maxPayloadSize
+    ) {
+      failWebsocketConnection(this.#handler, 1009, 'Payload size exceeds maximum allowed size')
+      return false
+    }
+
+    return true
+  }
+
   /**
    * Runs whenever a new chunk is received.
    * Callback is called whenever there are no more chunks buffering,
@@ -169,6 +188,10 @@ class ByteParser extends Writable {
         this.#info.masked = masked
         this.#info.fin = fin
         this.#info.fragmented = fragmented
+
+        if (this.#state === parserStates.READ_DATA && !this.#validatePayloadLength()) {
+          return
+        }
       } else if (this.#state === parserStates.PAYLOADLENGTH_16) {
         if (this.#byteOffset < 2) {
           return callback()
@@ -178,6 +201,10 @@ class ByteParser extends Writable {
 
         this.#info.payloadLength = buffer.readUInt16BE(0)
         this.#state = parserStates.READ_DATA
+
+        if (!this.#validatePayloadLength()) {
+          return
+        }
       } else if (this.#state === parserStates.PAYLOADLENGTH_64) {
         if (this.#byteOffset < 8) {
           return callback()
@@ -200,6 +227,10 @@ class ByteParser extends Writable {
 
         this.#info.payloadLength = lower
         this.#state = parserStates.READ_DATA
+
+        if (!this.#validatePayloadLength()) {
+          return
+        }
       } else if (this.#state === parserStates.READ_DATA) {
         if (this.#byteOffset < this.#info.payloadLength) {
           return callback()
@@ -224,29 +255,34 @@ class ByteParser extends Writable {
 
             this.#state = parserStates.INFO
           } else {
-            this.#extensions.get('permessage-deflate').decompress(body, this.#info.fin, (error, data) => {
-              if (error) {
-                // Use 1009 (Message Too Big) for decompression size limit errors
-                const code = error instanceof MessageSizeExceededError ? 1009 : 1007
-                failWebsocketConnection(this.#handler, code, error.message)
-                return
-              }
-
-              this.writeFragments(data)
+            this.#extensions.get('permessage-deflate').decompress(
+              body,
+              this.#info.fin,
+              (error, data) => {
+                if (error) {
+                  // Use 1009 (Message Too Big) for decompression size limit errors
+                  const code = error instanceof MessageSizeExceededError ? 1009 : 1007
+                  failWebsocketConnection(this.#handler, code, error.message)
+                  return
+                }
+
+                this.writeFragments(data)
+
+                if (!this.#info.fin) {
+                  this.#state = parserStates.INFO
+                  this.#loop = true
+                  this.run(callback)
+                  return
+                }
+
+                websocketMessageReceived(this.#handler, this.#info.binaryType, this.consumeFragments())
 
-              if (!this.#info.fin) {
-                this.#state = parserStates.INFO
                 this.#loop = true
+                this.#state = parserStates.INFO
                 this.run(callback)
-                return
-              }
-
-              websocketMessageReceived(this.#handler, this.#info.binaryType, this.consumeFragments())
-
-              this.#loop = true
-              this.#state = parserStates.INFO
-              this.run(callback)
-            })
+              },
+              this.#info.payloadLength
+            )
 
             this.#loop = false
             break

lib/web/websocket/websocket.js

@@ -468,7 +468,12 @@ class WebSocket extends EventTarget {
     // once this happens, the connection is open
     this.#handler.socket = response.socket
 
-    const parser = new ByteParser(this.#handler, parsedExtensions)
+    // Get maxPayloadSize from dispatcher options
+    const maxPayloadSize = this.#handler.controller.dispatcher?.webSocketOptions?.maxPayloadSize
+
+    const parser = new ByteParser(this.#handler, parsedExtensions, {
+      maxPayloadSize
+    })
     parser.on('drain', () => this.#handler.onParserDrain())
     parser.on('error', (err) => this.#handler.onParserError(err))