Fix SignTool check for managed module

src/Microsoft.DotNet.SignTool.Tests/SignToolTests.cs

@@ -429,6 +429,41 @@ public void EmptyPKT()
             });
         }
 
+        [Fact]
+        public void CrossGenNative()
+        {
+            // List of files to be considered for signing
+            var itemsToSign = new[]
+            {
+                GetResourcePath("CoreLibCrossARM.dll")
+            };
+
+            // Default signing information
+            var strongNameSignInfo = new Dictionary<string, SignInfo>()
+            {
+                { "581d91ccdfc4ea9c", new SignInfo("ArcadeCertTest", "ArcadeStrongTest") }
+            };
+
+            // Overriding information
+            var fileSignInfo = new Dictionary<ExplicitCertificateKey, string>()
+            {
+                { new ExplicitCertificateKey("EmptyPKT.dll"), "3PartySHA2" }
+            };
+
+            ValidateFileSignInfos(itemsToSign, strongNameSignInfo, fileSignInfo, s_fileExtensionSignInfo, new[]
+            {
+                "File 'CoreLibCrossARM.dll' Certificate='Microsoft400'",
+            });
+
+            ValidateGeneratedProject(itemsToSign, strongNameSignInfo, fileSignInfo, s_fileExtensionSignInfo, new[]
+            {
+$@"<FilesToSign Include=""{Path.Combine(_tmpDir, "CoreLibCrossARM.dll")}"">
+  <Authenticode>Microsoft400</Authenticode>
+</FilesToSign>",
+            });
+        }
+
+
         [Fact]
         public void DefaultCertificateForAssemblyWithoutStrongName()
         {

src/Microsoft.DotNet.SignTool/src/Configuration.cs

@@ -361,20 +361,19 @@ private static bool IsThirdPartyCertificate(string name)
 
         private static void GetPEInfo(string fullPath, out bool isManaged, out string publicKeyToken, out string targetFramework, out string copyright)
         {
-            AssemblyName assemblyName = ContentUtil.GetAssemblyName(fullPath);
+            isManaged = ContentUtil.IsManaged(fullPath);
 
-            if (assemblyName == null)
+            if (!isManaged)
             {
-                isManaged = false;
                 publicKeyToken = string.Empty;
                 targetFramework = string.Empty;
                 copyright = string.Empty;
                 return;
             }
 
+            AssemblyName assemblyName = AssemblyName.GetAssemblyName(fullPath);
             var pktBytes = assemblyName.GetPublicKeyToken();
 
-            isManaged = true;
             publicKeyToken = (pktBytes == null || pktBytes.Length == 0) ? string.Empty : string.Join("", pktBytes.Select(b => b.ToString("x2")));
             GetTargetFrameworkAndCopyright(fullPath, out targetFramework, out copyright);
         }

src/Microsoft.DotNet.SignTool/src/ContentUtil.cs

@@ -67,15 +67,14 @@ public static bool IsPublicSigned(PEReader peReader)
             return (header.Flags & CorFlags.StrongNameSigned) == CorFlags.StrongNameSigned;
         }
 
-        public static AssemblyName GetAssemblyName(string fullFilePath)
+        public static bool IsManaged(string filePath)
         {
-            try
+            using (var stream = new FileStream(filePath, FileMode.Open))
+            using (var peReader = new PEReader(stream))
             {
-                return AssemblyName.GetAssemblyName(fullFilePath);
-            }
-            catch
-            {
-                return null;
+                var corEntry = peReader.PEHeaders.PEHeader.CorHeaderTableDirectory;
+
+                return corEntry.RelativeVirtualAddress == 0x2008 && corEntry.Size == 0x48;
             }
         }
 

src/Microsoft.DotNet.SignTool/src/FileSignInfo.cs

@@ -48,7 +48,7 @@ internal static bool IsZipContainer(string path)
 
         internal bool IsPEFile() => IsPEFile(FileName);
 
-        internal bool IsManaged() => ContentUtil.GetAssemblyName(FullPath) != null;
+        internal bool IsManaged() => ContentUtil.IsManaged(FullPath);
 
         internal bool IsVsix() => IsVsix(FileName);