From d354d3ce4ea3c94b22c6efaf802df7e698618794 Mon Sep 17 00:00:00 2001
From: Miha Zupan <mihazupan.zupan1@gmail.com>
Date: Mon, 2 Jan 2023 12:09:46 +0100
Subject: [PATCH] Use IndexOfAnyValues in WebSocketValidate (#79974)

---
 .../Net/WebSockets/WebSocketValidate.cs       | 47 ++++++-------------
 1 file changed, 15 insertions(+), 32 deletions(-)

diff --git a/src/libraries/Common/src/System/Net/WebSockets/WebSocketValidate.cs b/src/libraries/Common/src/System/Net/WebSockets/WebSocketValidate.cs
index d0f3c6aedee73..95218a63269b0 100644
--- a/src/libraries/Common/src/System/Net/WebSockets/WebSocketValidate.cs
+++ b/src/libraries/Common/src/System/Net/WebSockets/WebSocketValidate.cs
@@ -1,8 +1,8 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Buffers;
 using System.Diagnostics;
-using System.Globalization;
 using System.Text;
 
 namespace System.Net.WebSockets
@@ -27,7 +27,10 @@ internal static partial class WebSocketValidate
         private const int CloseStatusCodeFailedTLSHandshake = 1015;
         private const int InvalidCloseStatusCodesFrom = 0;
         private const int InvalidCloseStatusCodesTo = 999;
-        private const string Separators = "()<>@,;:\\\"/[]?={} ";
+
+        // [0x21, 0x7E] except separators "()<>@,;:\\\"/[]?={} ".
+        private static readonly IndexOfAnyValues<char> s_validSubprotocolChars =
+            IndexOfAnyValues.Create("!#$%&'*+-.0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ^_`abcdefghijklmnopqrstuvwxyz|~");
 
         internal static void ThrowIfInvalidState(WebSocketState currentState, bool isDisposed, WebSocketState[] validStates)
         {
@@ -60,32 +63,16 @@ internal static void ValidateSubprotocol(string subProtocol)
                 throw new ArgumentException(SR.net_WebSockets_InvalidEmptySubProtocol, nameof(subProtocol));
             }
 
-            string? invalidChar = null;
-            int i = 0;
-            while (i < subProtocol.Length)
+            int indexOfInvalidChar = subProtocol.AsSpan().IndexOfAnyExcept(s_validSubprotocolChars);
+            if (indexOfInvalidChar >= 0)
             {
-                char ch = subProtocol[i];
-                if (ch < 0x21 || ch > 0x7e)
-                {
-                    invalidChar = $"[{(int)ch}]";
-                    break;
-                }
+                char invalidChar = subProtocol[indexOfInvalidChar];
 
-                if (!char.IsLetterOrDigit(ch) &&
-#pragma warning disable CA2249 // Consider using 'string.Contains' instead of 'string.IndexOf'.  This file is built into a project that doesn't have string.Contains(char).
-                    Separators.IndexOf(ch) >= 0)
-#pragma warning restore CA2249
-                {
-                    invalidChar = ch.ToString();
-                    break;
-                }
+                string invalidCharDescription = char.IsBetween(invalidChar, (char)0x21, (char)0x7E)
+                    ? invalidChar.ToString() // ASCII separator
+                    : $"[{(int)invalidChar}]";
 
-                i++;
-            }
-
-            if (invalidChar != null)
-            {
-                throw new ArgumentException(SR.Format(SR.net_WebSockets_InvalidCharInProtocolString, subProtocol, invalidChar), nameof(subProtocol));
+                throw new ArgumentException(SR.Format(SR.net_WebSockets_InvalidCharInProtocolString, subProtocol, invalidCharDescription), nameof(subProtocol));
             }
         }
 
@@ -112,13 +99,9 @@ internal static void ValidateCloseStatus(WebSocketCloseStatus closeStatus, strin
                     nameof(closeStatus));
             }
 
-            int length = 0;
-            if (!string.IsNullOrEmpty(statusDescription))
-            {
-                length = Encoding.UTF8.GetByteCount(statusDescription);
-            }
-
-            if (length > MaxControlFramePayloadLength)
+            if (!string.IsNullOrEmpty(statusDescription) &&
+                Encoding.UTF8.GetMaxByteCount(statusDescription.Length) > MaxControlFramePayloadLength &&
+                Encoding.UTF8.GetByteCount(statusDescription) > MaxControlFramePayloadLength)
             {
                 throw new ArgumentException(SR.Format(SR.net_WebSockets_InvalidCloseStatusDescription,
                     statusDescription,