Improve support for uncommon headers and PE directories layout

src/LibObjectFile.Tests/PE/PEReaderTests.cs

@@ -4,13 +4,10 @@
 
 using System;
 using System.IO;
-using System.Linq;
-using System.Runtime.InteropServices;
 using System.Threading.Tasks;
 using LibObjectFile.Diagnostics;
 using LibObjectFile.PE;
 using VerifyMSTest;
-using VerifyTests;
 
 namespace LibObjectFile.Tests.PE;
 
@@ -49,4 +46,33 @@ public async Task TestPrinter(string name)
             await Verifier.Verify(afterUpdateText).UseParameters(name).DisableRequireUniquePrefix();
         }
     }
+
+    [TestMethod]
+    public async Task TestTinyExe97Bytes()
+    {
+        // http://www.phreedom.org/research/tinype/
+        // TinyPE: The smallest possible PE file
+        // 97 bytes
+        byte[] data =
+        [
+            0x4D, 0x5A, 0x00, 0x00, 0x50, 0x45, 0x00, 0x00, 0x4C, 0x01, 0x01, 0x00, 0x6A, 0x2A, 0x58, 0xC3,
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x03, 0x01, 0x0B, 0x01, 0x08, 0x00,
+            0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x0C, 0x00, 0x00, 0x00,
+            0x04, 0x00, 0x00, 0x00, 0x0C, 0x00, 0x00, 0x00, 0x00, 0x00, 0x40, 0x00, 0x04, 0x00, 0x00, 0x00,
+            0x04, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00,
+            0x00, 0x00, 0x00, 0x00, 0x68, 0x00, 0x00, 0x00, 0x64, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+            0x02
+        ];
+
+        var stream = new MemoryStream();
+        stream.Write(data, 0, data.Length);
+        stream.Position = 0;
+
+        var peImage = PEFile.Read(stream);
+        var writer = new StringWriter();
+        peImage.Print(writer);
+        var afterReadText = writer.ToString();
+
+        await Verifier.Verify(afterReadText);
+    }
 }

src/LibObjectFile.Tests/Verified/PEReaderTests.TestPrinter_name=NativeConsole2Win64.exe.verified.txt

@@ -79,6 +79,7 @@ Data Directories
     [12] = PEImportAddressTableDirectory    Position = 0x00001E00, Size = 0x00000250, RVA = 0x00003000, VirtualSize = 0x00000250
     [13] = PEDelayImportDirectory           Position = 0x000029A8, Size = 0x00000040, RVA = 0x00003BA8, VirtualSize = 0x00000040
     [14] = null
+    [15] = null
 
 Section Headers
     [00]    .text PESection                        Position = 0x00000400, Size = 0x00001A00, RVA = 0x00001000, VirtualSize = 0x000019E9, Characteristics = 0x60000020 (ContainsCode, MemExecute, MemRead)

src/LibObjectFile.Tests/Verified/PEReaderTests.TestPrinter_name=NativeConsoleWin64.exe.verified.txt

@@ -79,6 +79,7 @@ Data Directories
     [12] = PEImportAddressTableDirectory    Position = 0x00001600, Size = 0x000001F0, RVA = 0x00003000, VirtualSize = 0x000001F0
     [13] = null
     [14] = null
+    [15] = null
 
 Section Headers
     [00]    .text PESection                        Position = 0x00000400, Size = 0x00001200, RVA = 0x00001000, VirtualSize = 0x000010C9, Characteristics = 0x60000020 (ContainsCode, MemExecute, MemRead)

src/LibObjectFile.Tests/Verified/PEReaderTests.TestPrinter_name=NativeLibraryWin64.dll.verified.txt

@@ -79,6 +79,7 @@ Data Directories
     [12] = PEImportAddressTableDirectory    Position = 0x00001400, Size = 0x000000E8, RVA = 0x00002000, VirtualSize = 0x000000E8
     [13] = null
     [14] = null
+    [15] = null
 
 Section Headers
     [00]    .text PESection                        Position = 0x00000400, Size = 0x00001000, RVA = 0x00001000, VirtualSize = 0x00000F18, Characteristics = 0x60000020 (ContainsCode, MemExecute, MemRead)

src/LibObjectFile.Tests/Verified/PEReaderTests.TestTinyExe97Bytes.verified.txt

@@ -0,0 +1,74 @@
+DOS Header
+    Magic                      = DOS
+    ByteCountOnLastPage        = 0x0
+    PageCount                  = 0x4550
+    RelocationCount            = 0x0
+    SizeOfParagraphsHeader     = 0x14C
+    MinExtraParagraphs         = 0x1
+    MaxExtraParagraphs         = 0x2A6A
+    InitialSSValue             = 0xC358
+    InitialSPValue             = 0x0
+    Checksum                   = 0x0
+    InitialIPValue             = 0x0
+    InitialCSValue             = 0x0
+    FileAddressRelocationTable = 0x4
+    OverlayNumber              = 0x103
+    Reserved                   = 0x10B, 0x8, 0x4, 0x0
+    OEMIdentifier              = 0x0
+    OEMInformation             = 0x0
+    Reserved2                  = 0x4, 0x0, 0xC, 0x0, 0x4, 0x0, 0xC, 0x0, 0x0, 0x40
+    FileAddressPEHeader        = 0x4
+
+DOS Stub
+    DosStub                    = 0 bytes
+
+COFF Header
+    Machine                    = I386
+    NumberOfSections           = 1
+    TimeDateStamp              = 3277335146
+    PointerToSymbolTable       = 0x0
+    NumberOfSymbols            = 0
+    SizeOfOptionalHeader       = 4
+    Characteristics            = RelocsStripped, ExecutableImage, Bit32Machine
+
+Optional Header
+    Magic                      = PE32
+    MajorLinkerVersion         = 8
+    MinorLinkerVersion         = 0
+    SizeOfCode                 = 0x4
+    SizeOfInitializedData      = 0x0
+    SizeOfUninitializedData    = 0x4
+    AddressOfEntryPoint        = 0xC
+    BaseOfCode                 = 0x4
+    BaseOfData                 = 0xC
+    ImageBase                  = 0x0
+    SectionAlignment           = 0x4
+    FileAlignment              = 0x4
+    MajorOperatingSystemVersion = 4
+    MinorOperatingSystemVersion = 0
+    MajorImageVersion          = 0
+    MinorImageVersion          = 0
+    MajorSubsystemVersion      = 4
+    MinorSubsystemVersion      = 0
+    Win32VersionValue          = 0x0
+    SizeOfImage                = 0x68
+    SizeOfHeaders              = 0x64
+    CheckSum                   = 0x0
+    Subsystem                  = WindowsGui
+    DllCharacteristics         = 0
+    SizeOfStackReserve         = 0x0
+    SizeOfStackCommit          = 0x0
+    SizeOfHeapReserve          = 0x0
+    SizeOfHeapCommit           = 0x0
+    LoaderFlags                = 0x0
+    NumberOfRvaAndSizes        = 0x0
+
+Section Headers
+    [00]         PESection                        Position = 0x0000000C, Size = 0x00000004, RVA = 0x0000000C, VirtualSize = 0x00000004, Characteristics = 0x00000004 (TypeGroup)
+
+Sections
+    --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+    [00]         PESection                        Position = 0x0000000C, Size = 0x00000004, RVA = 0x0000000C, VirtualSize = 0x00000004, Characteristics = 0x00000004 (TypeGroup)
+
+        [00] PEStreamSectionData              Position = 0x0000000C, Size = 0x00000004, RVA = 0x0000000C, VirtualSize = 0x00000004
+

src/LibObjectFile/Diagnostics/DiagnosticId.cs

@@ -130,8 +130,10 @@ public enum DiagnosticId
     PE_ERR_TooManySections = 3012,
     PE_ERR_FileAlignmentNotPowerOfTwo = 3013,
     PE_ERR_SectionAlignmentNotPowerOfTwo = 3014,
-    PE_ERR_SectionAlignmentLessThanFileAlignment = 315,
-
+    PE_ERR_SectionAlignmentLessThanFileAlignment = 3015,
+    PE_ERR_InvalidPEHeaderPosition = 3016,
+    PE_ERR_InvalidNumberOfDataDirectories = 3017,
+
     // PE Exception directory
     PE_ERR_InvalidExceptionDirectory_Entries = 3100,
     PE_ERR_InvalidExceptionDirectory_Entry = 3101,

src/LibObjectFile/PE/DataDirectory/PEDataDirectory.cs

@@ -46,7 +46,7 @@ internal static PEDataDirectory Create(PEDataDirectoryKind kind, bool is32Bits)
             PEDataDirectoryKind.DelayImport => new PEDelayImportDirectory(),
             PEDataDirectoryKind.ImportAddressTable => new PEImportAddressTableDirectory(),
             PEDataDirectoryKind.ClrMetadata => new PEClrMetadata(),
-            _ => throw new ArgumentOutOfRangeException(nameof(kind))
+            _ => new PEUnknownDirectory((int)kind)
         };
     }
-}
+}

src/LibObjectFile/PE/DataDirectory/PEDirectoryTable.cs

@@ -7,6 +7,7 @@
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Diagnostics;
+using System.Reflection;
 using System.Runtime.CompilerServices;
 
 namespace LibObjectFile.PE;
@@ -17,20 +18,81 @@ namespace LibObjectFile.PE;
 [DebuggerDisplay($"{nameof(PEDirectoryTable)} {nameof(Count)} = {{{nameof(Count)}}}")]
 public sealed class PEDirectoryTable : IEnumerable<PEDataDirectory>
 {
-    private InternalArray _entries;
+    private PEObjectBase?[] _entries;
     private int _count;
 
     internal PEDirectoryTable()
     {
+        _entries = [];
     }
 
-    public PEObjectBase? this[PEDataDirectoryKind kind] => _entries[(int)kind];
+    /// <summary>
+    /// Gets the directory entry at the specified index.
+    /// </summary>
+    /// <param name="index">The index of the directory entry to get.</param>
+    /// <returns>The directory entry at the specified index.</returns>
+    /// <exception cref="ArgumentOutOfRangeException">Thrown if the index is out of range.</exception>
+    public PEObjectBase? this[int index]
+    {
+        get
+        {
+            if (index < 0 || index >= _count)
+            {
+                throw new ArgumentOutOfRangeException(nameof(index));
+            }
+            return _entries[index];
+        }
+    }
 
     /// <summary>
-    /// Gets the number of directory entries in the array.
+    /// Gets the directory entry of the specified kind. Must be within the bounds of <see cref="Count"/>.
     /// </summary>
-    public int Count => _count;
-
+    /// <param name="kind">The kind of directory entry to get.</param>
+    /// <returns></returns>
+    /// <exception cref="ArgumentOutOfRangeException">Thrown if the kind is out of range.</exception>
+    public PEObjectBase? this[PEDataDirectoryKind kind]
+    {
+        get
+        {
+            int index = (int)(ushort)kind;
+            if (index < 0 || index >= _count)
+            {
+                throw new ArgumentOutOfRangeException(nameof(kind));
+            }
+            return _entries[(int)kind];
+        }
+    }
+
+    /// <summary>
+    /// Gets the maximum number of directory entries in the array.
+    /// </summary>
+    public int Count
+    {
+        get => _count;
+
+        set
+        {
+            ArgumentOutOfRangeException.ThrowIfLessThan(value, 0);
+
+            var previousCount = _count;
+            // If the count is reduced, we need to check that all entries are null after
+            for (int i = value; i < previousCount; i++)
+            {
+                if (_entries[i] is not null)
+                {
+                    throw new ArgumentOutOfRangeException(nameof(value), $"A non null directory entry was found at index {i}. This directory entry must be removed before setting a count of {value}");
+                }
+            }
+
+            if (_entries.Length < value)
+            {
+                Array.Resize(ref _entries, value);
+            }
+
+            _count = value;
+        }
+    }
+
     /// <summary>
     /// Gets the export directory information from the PE file.
     /// </summary>
@@ -112,60 +174,23 @@ internal PEDirectoryTable()
     [EditorBrowsable(EditorBrowsableState.Never)]
     public Enumerator GetEnumerator() => new(this);
 
-    internal void Set(PESecurityCertificateDirectory? directory)
-    {
-        var kind = PEDataDirectoryKind.SecurityCertificate;
-        ref var entry = ref _entries[(int)kind];
-        var previousEntry = entry;
-        entry = directory;
+    internal void Set(PESecurityCertificateDirectory? directory) => Set(PEDataDirectoryKind.SecurityCertificate, directory);
 
-        if (previousEntry is not null)
-        {
-            _count--;
-        }
+    internal void Set(PEDataDirectoryKind kind, PEObjectBase? directory) => Set((int)kind, directory);
 
-        if (directory is not null)
-        {
-            _count++;
-        }
-    }
-
-    internal void Set(PEDataDirectoryKind kind, PEDataDirectory? directory)
+    internal void Set(int index, PEObjectBase? directory)
     {
-        ref var entry = ref _entries[(int)kind];
-        var previousEntry = entry;
-        entry = directory;
-
-        if (previousEntry is not null)
+        if (index >= Count)
         {
-            _count--;
+            throw new ArgumentOutOfRangeException(nameof(index), $"The directory entry only accepts {Count} entries. Set the count explicitly to allow more entries.");
         }
 
-        if (directory is not null)
-        {
-            _count++;
-        }
+        _entries[index] = directory;
     }
-
-    internal int CalculateNumberOfEntries()
-    {
-        int count = 0;
-        ReadOnlySpan<PEObjectBase?> span = _entries;
-        for(int i = 0; i < span.Length; i++) 
-        {
-            if (_entries[i] is not null)
-            {
-                count = i + 1;
-            }
-        }
-
-        return count;
-    }
-
+
     internal unsafe void Write(PEImageWriter writer, ref uint position)
     {
-        var numberOfEntries = CalculateNumberOfEntries();
-        for (int i = 0; i < numberOfEntries; i++)
+        for (int i = 0; i < Count; i++)
         {
             ImageDataDirectory rawDataDirectory = default;
             var entry = _entries[i];
@@ -176,13 +201,7 @@ internal unsafe void Write(PEImageWriter writer, ref uint position)
             }
         }
 
-        position += (uint)(numberOfEntries * sizeof(ImageDataDirectory));
-    }
-
-    [InlineArray(15)]
-    private struct InternalArray
-    {
-        private PEObjectBase? _element;
+        position += (uint)(Count * sizeof(ImageDataDirectory));
     }
 
     /// <summary>

src/LibObjectFile/PE/DataDirectory/PESecurityCertificateDirectory.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Alexandre Mutel. All rights reserved.
+// Copyright (c) Alexandre Mutel. All rights reserved.
 // This file is licensed under the BSD-Clause 2 license.
 // See the license.txt file in the project root for more information.
 
@@ -71,9 +71,9 @@ public override unsafe void Read(PEImageReader reader)
             {
                 Revision = header.Revision,
                 Type = header.Type,
+                Data = reader.ReadAsStream(header.Length - 8)
             };
 
-            certificate.Data = reader.ReadAsStream(header.Length - 8);
             Certificates.Add(certificate);
 
             if (reader.HasErrors)

src/LibObjectFile/PE/DataDirectory/PEUnknownDirectory.cs

@@ -0,0 +1,17 @@
+// Copyright (c) Alexandre Mutel. All rights reserved.
+// This file is licensed under the BSD-Clause 2 license.
+// See the license.txt file in the project root for more information.
+
+namespace LibObjectFile.PE;
+
+/// <summary>
+/// Represents an unknown directory (when going beyond the known directories).
+/// </summary>
+public sealed class PEUnknownDirectory : PEDataDirectory
+{
+    internal PEUnknownDirectory(int index) : base((PEDataDirectoryKind)index)
+    {
+    }
+
+    protected override uint ComputeHeaderSize(PELayoutContext context) => 0;
+}