From ef8e1e017bde5083725373e9f100d8e78f72d9d3 Mon Sep 17 00:00:00 2001
From: Khafra <maitken033380023@gmail.com>
Date: Thu, 16 May 2024 10:25:09 -0400
Subject: [PATCH] fixup

---
 lib/web/websocket/permessage-deflate.js | 17 +++++++++++++++--
 lib/web/websocket/util.js               | 20 +++++++++++++++++++-
 2 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/lib/web/websocket/permessage-deflate.js b/lib/web/websocket/permessage-deflate.js
index 3918fd436c0..d349863888f 100644
--- a/lib/web/websocket/permessage-deflate.js
+++ b/lib/web/websocket/permessage-deflate.js
@@ -1,6 +1,7 @@
 'use strict'
 
-const { createInflateRaw } = require('node:zlib')
+const { createInflateRaw, Z_DEFAULT_WINDOWBITS } = require('node:zlib')
+const { isValidClientWindowBits } = require('./util')
 
 const tail = Buffer.from([0x00, 0x00, 0xff, 0xff])
 const kBuffer = Symbol('kBuffer')
@@ -14,6 +15,7 @@ class PerMessageDeflate {
 
   constructor (extensions) {
     this.#options.clientNoContextTakeover = extensions.has('client_no_context_takeover')
+    this.#options.clientMaxWindowBits = extensions.get('client_max_window_bits')
   }
 
   decompress (chunk, fin, callback) {
@@ -23,7 +25,18 @@ class PerMessageDeflate {
     // 2.  Decompress the resulting data using DEFLATE.
 
     if (!this.#inflate) {
-      this.#inflate = createInflateRaw(/* TODO */)
+      let windowBits = Z_DEFAULT_WINDOWBITS
+
+      if (this.#options.clientMaxWindowBits) { // empty values default to Z_DEFAULT_WINDOWBITS
+        if (!isValidClientWindowBits(this.#options.clientMaxWindowBits)) {
+          callback(new Error('Invalid client_max_window_bits'))
+          return
+        }
+
+        windowBits = Number.parseInt(this.#options.clientMaxWindowBits)
+      }
+
+      this.#inflate = createInflateRaw({ windowBits })
       this.#inflate[kBuffer] = []
       this.#inflate[kLength] = 0
 
diff --git a/lib/web/websocket/util.js b/lib/web/websocket/util.js
index 844cff2d007..8a2bae5de45 100644
--- a/lib/web/websocket/util.js
+++ b/lib/web/websocket/util.js
@@ -259,6 +259,23 @@ function parseExtensions (extensions) {
   return extensionList
 }
 
+/**
+ * @see https://www.rfc-editor.org/rfc/rfc7692#section-7.1.2.2
+ * @description "client-max-window-bits = 1*DIGIT"
+ * @param {string} value
+ */
+function isValidClientWindowBits (value) {
+  for (let i = 0; i < value.length; i++) {
+    const byte = value.charCodeAt(i)
+
+    if (byte < 0x30 || byte > 0x39) {
+      return false
+    }
+  }
+
+  return true
+}
+
 // https://nodejs.org/api/intl.html#detecting-internationalization-support
 const hasIntl = typeof process.versions.icu === 'string'
 const fatalDecoder = hasIntl ? new TextDecoder('utf-8', { fatal: true }) : undefined
@@ -291,5 +308,6 @@ module.exports = {
   isContinuationFrame,
   isTextBinaryFrame,
   isValidOpcode,
-  parseExtensions
+  parseExtensions,
+  isValidClientWindowBits
 }