Remove authenticode checks for nuget.protocol plugins (#6042)

src/NuGet.Core/NuGet.Protocol/GlobalSuppressions.cs

@@ -143,7 +143,6 @@
 [assembly: SuppressMessage("Build", "CA1031:Modify 'Receive' to catch a more specific allowed exception type, or rethrow the exception.", Justification = "<Pending>", Scope = "member", Target = "~M:NuGet.Protocol.Plugins.StandardInputReceiver.Receive(System.Object)")]
 [assembly: SuppressMessage("Build", "CA1031:Modify 'OnLineRead' to catch a more specific allowed exception type, or rethrow the exception.", Justification = "<Pending>", Scope = "member", Target = "~M:NuGet.Protocol.Plugins.StandardOutputReceiver.OnLineRead(System.Object,NuGet.Protocol.Plugins.LineReadEventArgs)")]
 [assembly: SuppressMessage("Build", "CA1031:Modify 'GetTimeout' to catch a more specific allowed exception type, or rethrow the exception.", Justification = "<Pending>", Scope = "member", Target = "~M:NuGet.Protocol.Plugins.TimeoutUtilities.GetTimeout(System.String,System.TimeSpan)~System.TimeSpan")]
-[assembly: SuppressMessage("Build", "CA1303:Method 'bool UnixAndMonoPlatformsEmbeddedSignatureVerifier.IsValid(string filePath)' passes a literal string as parameter 'message' of a call to 'ArgumentException.ArgumentException(string message)'. Retrieve the following string(s) from a resource table instead: \"filePath\".", Justification = "<Pending>", Scope = "member", Target = "~M:NuGet.Protocol.Plugins.UnixAndMonoPlatformsEmbeddedSignatureVerifier.IsValid(System.String)~System.Boolean")]
 [assembly: SuppressMessage("Build", "CA1801:Parameter ex of method ProxyAuthenticationRequired is never used. Remove the parameter or use it in the method body.", Justification = "Workaround for mono", Scope = "member", Target = "~M:NuGet.Protocol.ProxyAuthenticationHandler.AcquireCredentialsAsync(System.Uri,System.Guid,NuGet.Common.ILogger,System.Threading.CancellationToken)~System.Threading.Tasks.Task{System.Boolean}")]
 [assembly: SuppressMessage("Build", "CA1031:Modify 'PromptForProxyCredentialsAsync' to catch a more specific allowed exception type, or rethrow the exception.", Justification = "<Pending>", Scope = "member", Target = "~M:NuGet.Protocol.ProxyAuthenticationHandler.PromptForProxyCredentialsAsync(System.Uri,System.Net.IWebProxy,NuGet.Common.ILogger,System.Threading.CancellationToken)~System.Threading.Tasks.Task{System.Net.NetworkCredential}")]
 [assembly: SuppressMessage("Build", "CA1031:Modify 'SearchPage' to catch a more specific allowed exception type, or rethrow the exception.", Justification = "<Pending>", Scope = "member", Target = "~M:NuGet.Protocol.RawSearchResourceV3.SearchPage(System.String,NuGet.Protocol.Core.Types.SearchFilter,System.Int32,System.Int32,NuGet.Common.ILogger,System.Threading.CancellationToken)~System.Threading.Tasks.Task{Newtonsoft.Json.Linq.JObject}")]

src/NuGet.Core/NuGet.Protocol/Plugins/PluginDiscoverer.cs

@@ -20,23 +20,14 @@ public sealed class PluginDiscoverer : IPluginDiscoverer
         private readonly string _rawPluginPaths;
         private IEnumerable<PluginDiscoveryResult> _results;
         private readonly SemaphoreSlim _semaphore;
-        private readonly EmbeddedSignatureVerifier _verifier;
 
         /// <summary>
         /// Instantiates a new <see cref="PluginDiscoverer" /> class.
         /// </summary>
         /// <param name="rawPluginPaths">The raw semicolon-delimited list of supposed plugin file paths.</param>
-        /// <param name="verifier">An embedded signature verifier.</param>
-        /// <exception cref="ArgumentNullException">Thrown if <paramref name="verifier" /> is <see langword="null" />.</exception>
-        public PluginDiscoverer(string rawPluginPaths, EmbeddedSignatureVerifier verifier)
+        public PluginDiscoverer(string rawPluginPaths)
         {
-            if (verifier == null)
-            {
-                throw new ArgumentNullException(nameof(verifier));
-            }
-
             _rawPluginPaths = rawPluginPaths;
-            _verifier = verifier;
             _semaphore = new SemaphoreSlim(initialCount: 1, maxCount: 1);
         }
 
@@ -116,25 +107,18 @@ private List<PluginFile> GetPluginFiles(CancellationToken cancellationToken)
 
             foreach (var filePath in filePaths)
             {
-                cancellationToken.ThrowIfCancellationRequested();
-
-                if (PathValidator.IsValidLocalPath(filePath) || PathValidator.IsValidUncPath(filePath))
+                var pluginFile = new PluginFile(filePath, new Lazy<PluginFileState>(() =>
                 {
-                    if (File.Exists(filePath))
+                    if (PathValidator.IsValidLocalPath(filePath) || PathValidator.IsValidUncPath(filePath))
                     {
-                        var state = new Lazy<PluginFileState>(() => _verifier.IsValid(filePath) ? PluginFileState.Valid : PluginFileState.InvalidEmbeddedSignature);
-
-                        files.Add(new PluginFile(filePath, state));
+                        return File.Exists(filePath) ? PluginFileState.Valid : PluginFileState.NotFound;
                     }
                     else
                     {
-                        files.Add(new PluginFile(filePath, new Lazy<PluginFileState>(() => PluginFileState.NotFound)));
+                        return PluginFileState.InvalidFilePath;
                     }
-                }
-                else
-                {
-                    files.Add(new PluginFile(filePath, new Lazy<PluginFileState>(() => PluginFileState.InvalidFilePath)));
-                }
+                }));
+                files.Add(pluginFile);
             }
 
             return files;

src/NuGet.Core/NuGet.Protocol/Plugins/PluginFileState.cs

@@ -26,6 +26,7 @@ public enum PluginFileState
         /// <summary>
         /// The file exists but it has either no embedded signature or an invalid embedded signature.
         /// </summary>
+        /// <remarks>No longer used.</remarks>
         InvalidEmbeddedSignature
     }
 }

src/NuGet.Core/NuGet.Protocol/Plugins/PluginManager.cs

@@ -360,9 +360,7 @@ private async Task<IReadOnlyList<OperationClaim>> GetPluginOperationClaimsAsync(
 
         private PluginDiscoverer InitializeDiscoverer()
         {
-            var verifier = EmbeddedSignatureVerifier.Create();
-
-            return new PluginDiscoverer(_rawPluginPaths, verifier);
+            return new PluginDiscoverer(_rawPluginPaths);
         }
 
         private bool IsPluginPossiblyAvailable()