Fix Windows PE test failures

Author: xoofx

src/LibObjectFile.Tests/PE/PEReaderTests.cs

@@ -5,6 +5,7 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.Globalization;
 using System.IO;
 using System.Runtime.InteropServices;
 using System.Threading.Tasks;
@@ -162,6 +163,45 @@ public void TestCreatePE()
             Assert.AreEqual(156, process.ExitCode);
         }
     }
+
+    [TestMethod]
+    public void TestReadShortDosStub()
+    {
+        var pe = new PEFile
+        {
+            // Some Windows binaries use a stub shorter than e_cparhdr * 16.
+            DosStub = new byte[56]
+        };
+        using var stream = new MemoryStream();
+        pe.Write(stream);
+
+        stream.Position = 0;
+        var readPE = PEFile.Read(stream);
+
+        Assert.AreEqual(56, readPE.DosStub.Length);
+    }
+
+    [TestMethod]
+    public void TestPrinterUsesStableDateFormat()
+    {
+        var sourceFile = Path.Combine(AppContext.BaseDirectory, "PE", "NativeLibraryWin64.dll");
+        using var stream = File.OpenRead(sourceFile);
+        var peImage = PEFile.Read(stream);
+        var writer = new StringWriter();
+        var previousCulture = CultureInfo.CurrentCulture;
+
+        try
+        {
+            CultureInfo.CurrentCulture = CultureInfo.GetCultureInfo("fr-FR");
+            peImage.Print(writer);
+        }
+        finally
+        {
+            CultureInfo.CurrentCulture = previousCulture;
+        }
+
+        StringAssert.Contains(writer.ToString(), "TimeStamp = 02/07/2106 06:28:15");
+    }
 
     [TestMethod]
     [DynamicData(nameof(GetWindowsExeAndDlls))]
@@ -285,4 +325,4 @@ public async Task TestTinyExe97Bytes()
 
         await Verifier.Verify(afterReadText);
     }
-}
+}

src/LibObjectFile/PE/DataDirectory/PEResourceDirectoryEntry.cs

@@ -7,6 +7,7 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.Globalization;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using System.Text;
@@ -254,7 +255,7 @@ protected override bool PrintMembers(StringBuilder builder)
             builder.Append(", ");
         }
 
-        builder.Append($"ByNames[{ByNames.Count}], ByIds[{ByIds.Count}] , TimeDateStamp = {TimeDateStamp}, MajorVersion = {MajorVersion}, MinorVersion = {MinorVersion}");
+        builder.Append($"ByNames[{ByNames.Count}], ByIds[{ByIds.Count}] , TimeDateStamp = {TimeDateStamp.ToString("MM/dd/yyyy HH:mm:ss", CultureInfo.InvariantCulture)}, MajorVersion = {MajorVersion}, MinorVersion = {MinorVersion}");
 
         return true;
     }

src/LibObjectFile/PE/PEFile.Read.cs

@@ -91,10 +91,13 @@ public override unsafe void Read(PEImageReader reader)
             // Read the DOS stub
             var dosStubSize = DosHeader.SizeOfParagraphsHeader * 16;
 
-            if (dosStubSize + sizeof(PEDosHeader) > pePosition)
+            // e_cparhdr describes the DOS header rather than the space available before
+            // the PE header. Some Windows binaries have less than e_cparhdr * 16 bytes
+            // available for the stub, so limit the stub to the actual available space.
+            var availableDosStubSize = pePosition - sizeof(PEDosHeader);
+            if (dosStubSize > availableDosStubSize)
             {
-                diagnostics.Error(DiagnosticId.PE_ERR_InvalidDosStubSize, $"Invalid DOS stub size {dosStubSize} going beyond the PE header");
-                return;
+                dosStubSize = (int)availableDosStubSize;
             }
 
             if (dosStubSize > 0)
@@ -743,4 +746,4 @@ private static void FillDirectoryWithStreams(PEImageReader imageReader, PEDataDi
     {
         FillSectionDataWithMissingStreams(imageReader, directory, directory.Content, (uint)(directory.Position + directory.HeaderSize), (uint)(directory.Size - directory.HeaderSize), null);
     }
-}
+}

src/LibObjectFile/PE/PEPrinter.cs

@@ -3,6 +3,7 @@
 // See the license.txt file in the project root for more information.
 
 using System;
+using System.Globalization;
 using System.IO;
 using LibObjectFile.IO;
 using static System.Runtime.InteropServices.JavaScript.JSType;
@@ -413,7 +414,7 @@ private static void Print(PEExceptionDirectory data, ref TextWriterIndenter writ
 
     private static void Print(PEExportDirectory data, ref TextWriterIndenter writer)
     {
-        writer.WriteLine($"{nameof(PEExportDirectory.TimeStamp)} = {data.TimeStamp}");
+        writer.WriteLine($"{nameof(PEExportDirectory.TimeStamp)} = {FormatTimestamp(data.TimeStamp)}");
         writer.WriteLine($"{nameof(PEExportDirectory.MajorVersion)} = {data.MajorVersion}");
         writer.WriteLine($"{nameof(PEExportDirectory.MinorVersion)} = {data.MinorVersion}");
         writer.WriteLine($"{nameof(PEExportDirectory.OrdinalBase)} = 0x{data.OrdinalBase:X}");
@@ -575,7 +576,7 @@ private static void Print(PEResourceEntry data, ref TextWriterIndenter writer)
                 writer.WriteLine($"> CodePage = {resourceFile.CodePage?.EncodingName ?? "null"}, Data = {resourceFile.Data}");
                 break;
             case PEResourceDirectoryEntry dir:
-                writer.WriteLine($"> ByNames[{dir.ByNames.Count}], ByIds[{dir.ByIds.Count}] , TimeDateStamp = {dir.TimeDateStamp}, Version = {dir.MajorVersion}.{dir.MinorVersion}");
+                writer.WriteLine($"> ByNames[{dir.ByNames.Count}], ByIds[{dir.ByIds.Count}] , TimeDateStamp = {FormatTimestamp(dir.TimeDateStamp)}, Version = {dir.MajorVersion}.{dir.MinorVersion}");
                 writer.Indent();
 
                 for (var i = 0; i < dir.ByNames.Count; i++)
@@ -740,4 +741,6 @@ static string PEParent(PEObjectBase? obj)
             return "";
         }
     }
-}
+
+    private static string FormatTimestamp(DateTime timestamp) => timestamp.ToString("MM/dd/yyyy HH:mm:ss", CultureInfo.InvariantCulture);
+}