public void GetContentToSign_MultiBlobHeader()
        {
            var builder = new BlobBuilder(16);

            builder.WriteBytes(0, 16);
            builder.WriteBytes(1, 16);
            builder.WriteBytes(2, 16);
            builder.WriteBytes(3, 16);
            builder.WriteBytes(4, 2);
            var snFixup = builder.ReserveBytes(1);

            builder.WriteBytes(4, 13);
            builder.WriteBytes(5, 10);
            Assert.Equal(6, builder.GetBlobs().Count());

            AssertEx.Equal(
                new[]
            {
                "0: [0, 16)",
                "1: [0, 16)",
                "2: [0, 1)",
                "4: [0, 2)",
                "4: [3, 16)",
                "5: [0, 10)"
            },
                GetBlobRanges(builder, PEBuilder.GetContentToSign(builder, peHeadersSize: 33, peHeaderAlignment: 64, strongNameSignatureFixup: snFixup)));
        }
        public void GetContentToSign_HeaderAndFixupInDistinctBlobs()
        {
            var builder = new BlobBuilder(16);

            builder.WriteBytes(0, 16);
            builder.WriteBytes(1, 16);
            builder.WriteBytes(2, 16);
            builder.WriteBytes(3, 16);
            var snFixup = builder.ReserveBytes(16);

            builder.WriteBytes(5, 16);
            builder.WriteBytes(6, 1);
            Assert.Equal(7, builder.GetBlobs().Count());

            AssertEx.Equal(
                new[]
            {
                "0: [0, 1)",
                "0: [4, 16)",
                "1: [0, 16)",
                "2: [0, 16)",
                "3: [0, 16)",
                "4: [0, 0)",
                "4: [16, 16)",
                "5: [0, 16)",
                "6: [0, 1)"
            },
                GetBlobRanges(builder, PEBuilder.GetContentToSign(builder, peHeadersSize: 1, peHeaderAlignment: 4, strongNameSignatureFixup: snFixup)));
        }
Example #3
0
        private static void WritePEImage(Stream peStream, MetadataBuilder metadataBuilder, BlobBuilder ilBuilder, MethodDefinitionHandle entryPointHandle)
        {
            var mappedFieldDataBuilder     = new BlobBuilder();
            var managedResourceDataBuilder = new BlobBuilder();

            var peBuilder = new PEBuilder(
                machine: 0,
                sectionAlignment: 0x2000,
                fileAlignment: 0x200,
                imageBase: 0x00400000,
                majorLinkerVersion: 0x30, // (what is ref.emit using?)
                minorLinkerVersion: 0,
                majorOperatingSystemVersion: 4,
                minorOperatingSystemVersion: 0,
                majorImageVersion: 0,
                minorImageVersion: 0,
                majorSubsystemVersion: 4,
                minorSubsystemVersion: 0,
                subsystem: Subsystem.WindowsCui,
                dllCharacteristics: DllCharacteristics.DynamicBase | DllCharacteristics.NxCompatible | DllCharacteristics.NoSeh | DllCharacteristics.TerminalServerAware,
                imageCharacteristics: entryPointHandle.IsNil ? Characteristics.Dll : Characteristics.ExecutableImage,
                sizeOfStackReserve: 0x00100000,
                sizeOfStackCommit: 0x1000,
                sizeOfHeapReserve: 0x00100000,
                sizeOfHeapCommit: 0x1000);

            var peDirectoriesBuilder = new PEDirectoriesBuilder();

            peBuilder.AddManagedSections(
                peDirectoriesBuilder,
                new TypeSystemMetadataSerializer(metadataBuilder, "v4.0.30319", isMinimalDelta: false),
                ilBuilder,
                mappedFieldDataBuilder,
                managedResourceDataBuilder,
                nativeResourceSectionSerializer: null,
                strongNameSignatureSize: 0,
                entryPoint: entryPointHandle,
                pdbPathOpt: null,
                nativePdbContentId: default(ContentId),
                portablePdbContentId: default(ContentId),
                corFlags: CorFlags.ILOnly);

            var       peBlob = new BlobBuilder();
            ContentId peContentId;

            peBuilder.Serialize(peBlob, peDirectoriesBuilder, out peContentId);

            peBlob.WriteContentTo(peStream);
        }
        private static void WritePEImage(Stream peStream, MetadataBuilder metadataBuilder, BlobBuilder ilBuilder, MethodDefinitionHandle entryPointHandle)
        {
            var mappedFieldDataBuilder = new BlobBuilder();
            var managedResourceDataBuilder = new BlobBuilder();

            var peBuilder = new PEBuilder(
                machine: 0,
                sectionAlignment: 0x2000,
                fileAlignment: 0x200,
                imageBase: 0x00400000,
                majorLinkerVersion: 0x30, // (what is ref.emit using?)
                minorLinkerVersion: 0,
                majorOperatingSystemVersion: 4,
                minorOperatingSystemVersion: 0,
                majorImageVersion: 0,
                minorImageVersion: 0,
                majorSubsystemVersion: 4,
                minorSubsystemVersion: 0,
                subsystem: Subsystem.WindowsCui,
                dllCharacteristics: DllCharacteristics.DynamicBase | DllCharacteristics.NxCompatible | DllCharacteristics.NoSeh | DllCharacteristics.TerminalServerAware,
                imageCharacteristics: entryPointHandle.IsNil ? Characteristics.Dll : Characteristics.ExecutableImage,
                sizeOfStackReserve: 0x00100000,
                sizeOfStackCommit: 0x1000,
                sizeOfHeapReserve: 0x00100000,
                sizeOfHeapCommit: 0x1000);

            var peDirectoriesBuilder = new PEDirectoriesBuilder();

            peBuilder.AddManagedSections(
                peDirectoriesBuilder,
                new TypeSystemMetadataSerializer(metadataBuilder, "v4.0.30319", isMinimalDelta: false),
                ilBuilder,
                mappedFieldDataBuilder,
                managedResourceDataBuilder,
                nativeResourceSectionSerializer: null,
                strongNameSignatureSize: 0,
                entryPoint: entryPointHandle,
                pdbPathOpt: null,
                nativePdbContentId: default(ContentId),
                portablePdbContentId: default(ContentId),
                corFlags: CorFlags.ILOnly);

            var peBlob = new BlobBuilder();
            ContentId peContentId;
            peBuilder.Serialize(peBlob, peDirectoriesBuilder, out peContentId);

            peBlob.WriteContentTo(peStream);
        }
        public void GetPrefixBlob()
        {
            byte[] buffer = new byte[] { 0, 1, 2, 3, 4, 5 };

            // [0, 1, <2, 3>, 4, 5]
            var b = PEBuilder.GetPrefixBlob(new Blob(buffer, start: 0, length: 6), new Blob(buffer, start: 2, length: 2));

            Assert.Same(buffer, b.Buffer);
            Assert.Equal(0, b.Start);
            Assert.Equal(2, b.Length);

            // [0, 1, <2, 3>, 4], 5
            b = PEBuilder.GetPrefixBlob(new Blob(buffer, start: 0, length: 5), new Blob(buffer, start: 2, length: 2));
            Assert.Same(buffer, b.Buffer);
            Assert.Equal(0, b.Start);
            Assert.Equal(2, b.Length);

            // 0, [1, <2, 3>, 4], 5
            b = PEBuilder.GetPrefixBlob(new Blob(buffer, start: 1, length: 4), new Blob(buffer, start: 2, length: 2));
            Assert.Same(buffer, b.Buffer);
            Assert.Equal(1, b.Start);
            Assert.Equal(1, b.Length);

            // 0, 1, [<2, 3>, 4], 5
            b = PEBuilder.GetPrefixBlob(new Blob(buffer, start: 2, length: 3), new Blob(buffer, start: 2, length: 2));
            Assert.Same(buffer, b.Buffer);
            Assert.Equal(2, b.Start);
            Assert.Equal(0, b.Length);

            // 0, 1, [<2, 3>], 4, 5
            b = PEBuilder.GetPrefixBlob(new Blob(buffer, start: 2, length: 2), new Blob(buffer, start: 2, length: 2));
            Assert.Same(buffer, b.Buffer);
            Assert.Equal(2, b.Start);
            Assert.Equal(0, b.Length);

            // 0, 1, [<2>], 3, 4, 5
            b = PEBuilder.GetPrefixBlob(new Blob(buffer, start: 2, length: 1), new Blob(buffer, start: 2, length: 1));
            Assert.Same(buffer, b.Buffer);
            Assert.Equal(2, b.Start);
            Assert.Equal(0, b.Length);

            // 0, 1, [<>]2, 3, 4, 5
            b = PEBuilder.GetPrefixBlob(new Blob(buffer, start: 2, length: 0), new Blob(buffer, start: 2, length: 0));
            Assert.Same(buffer, b.Buffer);
            Assert.Equal(2, b.Start);
            Assert.Equal(0, b.Length);
        }
        private static bool TestChecksumAndAuthenticodeSignature(Stream peStream, byte[] privateKeyOpt = null)
        {
            var  peHeaders        = new PEHeaders(peStream);
            bool is32bit          = peHeaders.PEHeader.Magic == PEMagic.PE32;
            uint expectedChecksum = peHeaders.PEHeader.CheckSum;
            int  peHeadersSize    = peHeaders.PEHeaderStartOffset + PEHeader.Size(is32bit) + SectionHeader.Size * peHeaders.SectionHeaders.Length;

            peStream.Position = 0;

            if (expectedChecksum == 0)
            {
                // not signed
                return(false);
            }

            int peSize  = (int)peStream.Length;
            var peImage = new BlobBuilder(peSize);

            Assert.Equal(peSize, peImage.TryWriteBytes(peStream, peSize));

            var buffer       = peImage.GetBlobs().Single().Buffer;
            var checksumBlob = new Blob(buffer, peHeaders.PEHeaderStartOffset + PEHeader.OffsetOfChecksum, sizeof(uint));

            uint checksum = PEBuilder.CalculateChecksum(peImage, checksumBlob);

            Assert.Equal(expectedChecksum, checksum);

            // validate signature:
            if (privateKeyOpt != null)
            {
                // signature is calculated with checksum zeroed:
                new BlobWriter(checksumBlob).WriteUInt32(0);

                int snOffset;
                Assert.True(peHeaders.TryGetDirectoryOffset(peHeaders.CorHeader.StrongNameSignatureDirectory, out snOffset));
                var snBlob            = new Blob(buffer, snOffset, peHeaders.CorHeader.StrongNameSignatureDirectory.Size);
                var expectedSignature = snBlob.GetBytes().ToArray();
                var signature         = SigningUtilities.CalculateRsaSignature(PEBuilder.GetContentToSign(peImage, peHeadersSize, peHeaders.PEHeader.FileAlignment, snBlob), privateKeyOpt);
                AssertEx.Equal(expectedSignature, signature);
            }

            return(true);
        }
        public void GetContentToSign_AllInOneBlob()
        {
            var builder = new BlobBuilder(16);

            builder.WriteBytes(1, 5);
            var snFixup = builder.ReserveBytes(5);

            builder.WriteBytes(2, 6);
            Assert.Equal(1, builder.GetBlobs().Count());

            AssertEx.Equal(
                new[]
            {
                "0: [0, 2)",
                "0: [4, 5)",
                "0: [10, 16)"
            },
                GetBlobRanges(builder, PEBuilder.GetContentToSign(builder, peHeadersSize: 2, peHeaderAlignment: 4, strongNameSignatureFixup: snFixup)));
        }
Example #8
0
        public static bool WritePeToStream(
            EmitContext context,
            CommonMessageProvider messageProvider,
            Func<Stream> getPeStream,
            Func<Stream> getPortablePdbStreamOpt,
            PdbWriter nativePdbWriterOpt,
            string pdbPathOpt,
            bool allowMissingMethodBodies,
            bool isDeterministic,
            CancellationToken cancellationToken)
        {
            // If PDB writer is given, we have to have PDB path.
            Debug.Assert(nativePdbWriterOpt == null || pdbPathOpt != null);

            var mdWriter = FullMetadataWriter.Create(context, messageProvider, allowMissingMethodBodies, isDeterministic, getPortablePdbStreamOpt != null, cancellationToken);

            var properties = context.Module.Properties;

            nativePdbWriterOpt?.SetMetadataEmitter(mdWriter);

            // Since we are producing a full assembly, we should not have a module version ID
            // imposed ahead-of time. Instead we will compute a deterministic module version ID
            // based on the contents of the generated stream.
            Debug.Assert(properties.PersistentIdentifier == default(Guid));

            var ilBuilder = new BlobBuilder(32 * 1024);
            var mappedFieldDataBuilder = new BlobBuilder();
            var managedResourceBuilder = new BlobBuilder(1024);

            Blob mvidFixup;
            mdWriter.BuildMetadataAndIL(
                nativePdbWriterOpt,
                ilBuilder,
                mappedFieldDataBuilder,
                managedResourceBuilder,
                out mvidFixup);

            MethodDefinitionHandle entryPointHandle;
            MethodDefinitionHandle debugEntryPointHandle;
            mdWriter.GetEntryPoints(out entryPointHandle, out debugEntryPointHandle);
            
            if (!debugEntryPointHandle.IsNil)
            {
                nativePdbWriterOpt?.SetEntryPoint((uint)MetadataTokens.GetToken(debugEntryPointHandle));
            }

            if (nativePdbWriterOpt != null)
            {
                var assembly = mdWriter.Module.AsAssembly;
                if (assembly != null && assembly.Kind == OutputKind.WindowsRuntimeMetadata)
                {
                    // Dev12: If compiling to winmdobj, we need to add to PDB source spans of
                    //        all types and members for better error reporting by WinMDExp.
                    nativePdbWriterOpt.WriteDefinitionLocations(mdWriter.Module.GetSymbolToLocationMap());
                }
                else
                {
#if DEBUG
                    // validate that all definitions are writable
                    // if same scenario would happen in an winmdobj project
                    nativePdbWriterOpt.AssertAllDefinitionsHaveTokens(mdWriter.Module.GetSymbolToLocationMap());
#endif
                }
            }

            Stream peStream = getPeStream();
            if (peStream == null)
            {
                return false;
            }

            ContentId nativePdbContentId = nativePdbWriterOpt?.GetContentId() ?? default(ContentId);

            // the writer shall not be used after this point for writing:
            nativePdbWriterOpt = null;

            var metadataSerializer = mdWriter.GetTypeSystemMetadataSerializer();

            var peBuilder = new PEBuilder(
                machine: properties.Machine,
                sectionAlignment: properties.SectionAlignment,
                fileAlignment: properties.FileAlignment,
                imageBase: properties.BaseAddress,
                majorLinkerVersion: properties.LinkerMajorVersion,
                minorLinkerVersion: properties.LinkerMinorVersion,
                majorOperatingSystemVersion: 4,
                minorOperatingSystemVersion: 0,
                majorImageVersion: 0,
                minorImageVersion: 0,
                majorSubsystemVersion: properties.MajorSubsystemVersion,
                minorSubsystemVersion: properties.MinorSubsystemVersion,
                subsystem: properties.Subsystem,
                dllCharacteristics: properties.DllCharacteristics,
                imageCharacteristics: properties.ImageCharacteristics,
                sizeOfStackReserve: properties.SizeOfStackReserve,
                sizeOfStackCommit: properties.SizeOfStackCommit,
                sizeOfHeapReserve: properties.SizeOfHeapReserve,
                sizeOfHeapCommit: properties.SizeOfHeapCommit,
                deterministicIdProvider: isDeterministic ? new Func<BlobBuilder, ContentId>(content => ContentId.FromHash(CryptographicHashProvider.ComputeSha1(content))) : null);

            ContentId portablePdbContentId;
            if (mdWriter.EmitStandaloneDebugMetadata)
            {
                Debug.Assert(getPortablePdbStreamOpt != null);

                var debugMetadataBuilder = new BlobBuilder();
                var debugMetadataSerializer = mdWriter.GetStandaloneDebugMetadataSerializer(metadataSerializer.MetadataSizes, debugEntryPointHandle);
                debugMetadataSerializer.SerializeMetadata(debugMetadataBuilder, peBuilder.IdProvider, out portablePdbContentId);

                // write to Portable PDB stream:
                Stream portablePdbStream = getPortablePdbStreamOpt();
                if (portablePdbStream != null)
                {
                    debugMetadataBuilder.WriteContentTo(portablePdbStream);
                }
            }
            else
            {
                portablePdbContentId = default(ContentId);
            }

            var peDirectoriesBuilder = new PEDirectoriesBuilder();

            peBuilder.AddManagedSections(
                peDirectoriesBuilder,
                metadataSerializer,
                ilBuilder,
                mappedFieldDataBuilder,
                managedResourceBuilder,
                CreateNativeResourceSectionSerializer(context.Module),
                CalculateStrongNameSignatureSize(context.Module),
                entryPointHandle,
                pdbPathOpt,
                nativePdbContentId,
                portablePdbContentId,
                properties.CorFlags);

            var peBlob = new BlobBuilder();
            ContentId peContentId;
            peBuilder.Serialize(peBlob, peDirectoriesBuilder, out peContentId);

            // Patch MVID
            if (!mvidFixup.IsDefault)
            {
                var mvidWriter = new BlobWriter(mvidFixup);
                mvidWriter.WriteBytes(peContentId.Guid);
                Debug.Assert(mvidWriter.RemainingBytes == 0);
            }

            try
            {
                peBlob.WriteContentTo(peStream);
            }
            catch (Exception e) when (!(e is OperationCanceledException))
            {
                throw new PeWritingException(e);
            }

            return true;
        }
Example #9
0
        public static void AddManagedSections(
            this PEBuilder peBuilder,
            PEDirectoriesBuilder peDirectoriesBuilder,
            TypeSystemMetadataSerializer metadataSerializer,
            BlobBuilder ilStream,
            BlobBuilder mappedFieldData,
            BlobBuilder managedResourceData,
            Action <BlobBuilder, PESectionLocation> nativeResourceSectionSerializer, // opt
            int strongNameSignatureSize,                                             // TODO
            MethodDefinitionHandle entryPoint,
            string pdbPathOpt,                                                       // TODO
            ContentId nativePdbContentId,                                            // TODO
            ContentId portablePdbContentId,                                          // TODO
            CorFlags corFlags)
        {
            int entryPointAddress = 0;

            // .text
            peBuilder.AddSection(".text", SectionCharacteristics.MemRead | SectionCharacteristics.MemExecute | SectionCharacteristics.ContainsCode, location =>
            {
                var sectionBuilder  = new BlobBuilder();
                var metadataBuilder = new BlobBuilder();

                var metadataSizes = metadataSerializer.MetadataSizes;

                var textSection = new ManagedTextSection(
                    metadataSizes.MetadataSize,
                    ilStreamSize: ilStream.Count,
                    mappedFieldDataSize: mappedFieldData.Count,
                    resourceDataSize: managedResourceData.Count,
                    strongNameSignatureSize: strongNameSignatureSize,
                    imageCharacteristics: peBuilder.ImageCharacteristics,
                    machine: peBuilder.Machine,
                    pdbPathOpt: pdbPathOpt,
                    isDeterministic: peBuilder.IsDeterministic);

                int methodBodyStreamRva      = location.RelativeVirtualAddress + textSection.OffsetToILStream;
                int mappedFieldDataStreamRva = location.RelativeVirtualAddress + textSection.CalculateOffsetToMappedFieldDataStream();
                metadataSerializer.SerializeMetadata(metadataBuilder, methodBodyStreamRva, mappedFieldDataStreamRva);

                BlobBuilder debugTableBuilderOpt;
                if (pdbPathOpt != null || peBuilder.IsDeterministic)
                {
                    debugTableBuilderOpt = new BlobBuilder();
                    textSection.WriteDebugTable(debugTableBuilderOpt, location, nativePdbContentId, portablePdbContentId);
                }
                else
                {
                    debugTableBuilderOpt = null;
                }

                entryPointAddress = textSection.GetEntryPointAddress(location.RelativeVirtualAddress);

                textSection.Serialize(
                    sectionBuilder,
                    location.RelativeVirtualAddress,
                    entryPoint.IsNil ? 0 : MetadataTokens.GetToken(entryPoint),
                    corFlags,
                    peBuilder.ImageBase,
                    metadataBuilder,
                    ilStream,
                    mappedFieldData,
                    managedResourceData,
                    debugTableBuilderOpt);

                peDirectoriesBuilder.AddressOfEntryPoint = entryPointAddress;
                peDirectoriesBuilder.DebugTable          = textSection.GetDebugDirectoryEntry(location.RelativeVirtualAddress);
                peDirectoriesBuilder.ImportAddressTable  = textSection.GetImportAddressTableDirectoryEntry(location.RelativeVirtualAddress);
                peDirectoriesBuilder.ImportTable         = textSection.GetImportTableDirectoryEntry(location.RelativeVirtualAddress);
                peDirectoriesBuilder.CorHeaderTable      = textSection.GetCorHeaderDirectoryEntry(location.RelativeVirtualAddress);

                return(sectionBuilder);
            });

            // .rsrc
            if (nativeResourceSectionSerializer != null)
            {
                peBuilder.AddSection(".rsrc", SectionCharacteristics.MemRead | SectionCharacteristics.ContainsInitializedData, location =>
                {
                    var sectionBuilder = new BlobBuilder();
                    nativeResourceSectionSerializer(sectionBuilder, location);
                    peDirectoriesBuilder.ResourceTable = new DirectoryEntry(location.RelativeVirtualAddress, sectionBuilder.Count);
                    return(sectionBuilder);
                });
            }

            // .reloc
            if (peBuilder.Machine == Machine.I386 || peBuilder.Machine == 0)
            {
                peBuilder.AddSection(".reloc", SectionCharacteristics.MemRead | SectionCharacteristics.MemDiscardable | SectionCharacteristics.ContainsInitializedData, location =>
                {
                    var sectionBuilder = new BlobBuilder();
                    WriteRelocSection(sectionBuilder, peBuilder.Machine, entryPointAddress);

                    peDirectoriesBuilder.BaseRelocationTable = new DirectoryEntry(location.RelativeVirtualAddress, sectionBuilder.Count);
                    return(sectionBuilder);
                });
            }
        }
        public static bool WritePeToStream(
            EmitContext context,
            CommonMessageProvider messageProvider,
            Func <Stream> getPeStream,
            Func <Stream> getPortablePdbStreamOpt,
            PdbWriter nativePdbWriterOpt,
            string pdbPathOpt,
            bool allowMissingMethodBodies,
            bool isDeterministic,
            CancellationToken cancellationToken)
        {
            // If PDB writer is given, we have to have PDB path.
            Debug.Assert(nativePdbWriterOpt == null || pdbPathOpt != null);

            var mdWriter = FullMetadataWriter.Create(context, messageProvider, allowMissingMethodBodies, isDeterministic, getPortablePdbStreamOpt != null, cancellationToken);

            var properties = context.Module.Properties;

            nativePdbWriterOpt?.SetMetadataEmitter(mdWriter);

            // Since we are producing a full assembly, we should not have a module version ID
            // imposed ahead-of time. Instead we will compute a deterministic module version ID
            // based on the contents of the generated stream.
            Debug.Assert(properties.PersistentIdentifier == default(Guid));

            var ilBuilder = new BlobBuilder(32 * 1024);
            var mappedFieldDataBuilder = new BlobBuilder();
            var managedResourceBuilder = new BlobBuilder(1024);

            Blob mvidFixup;

            mdWriter.BuildMetadataAndIL(
                nativePdbWriterOpt,
                ilBuilder,
                mappedFieldDataBuilder,
                managedResourceBuilder,
                out mvidFixup);

            MethodDefinitionHandle entryPointHandle;
            MethodDefinitionHandle debugEntryPointHandle;

            mdWriter.GetEntryPoints(out entryPointHandle, out debugEntryPointHandle);

            if (!debugEntryPointHandle.IsNil)
            {
                nativePdbWriterOpt?.SetEntryPoint((uint)MetadataTokens.GetToken(debugEntryPointHandle));
            }

            if (nativePdbWriterOpt != null)
            {
                var assembly = mdWriter.Module.AsAssembly;
                if (assembly != null && assembly.Kind == OutputKind.WindowsRuntimeMetadata)
                {
                    // Dev12: If compiling to winmdobj, we need to add to PDB source spans of
                    //        all types and members for better error reporting by WinMDExp.
                    nativePdbWriterOpt.WriteDefinitionLocations(mdWriter.Module.GetSymbolToLocationMap());
                }
                else
                {
#if DEBUG
                    // validate that all definitions are writable
                    // if same scenario would happen in an winmdobj project
                    nativePdbWriterOpt.AssertAllDefinitionsHaveTokens(mdWriter.Module.GetSymbolToLocationMap());
#endif
                }
            }

            Stream peStream = getPeStream();
            if (peStream == null)
            {
                return(false);
            }

            ContentId nativePdbContentId = nativePdbWriterOpt?.GetContentId() ?? default(ContentId);

            // the writer shall not be used after this point for writing:
            nativePdbWriterOpt = null;

            var metadataSerializer = mdWriter.GetTypeSystemMetadataSerializer();

            var peBuilder = new PEBuilder(
                machine: properties.Machine,
                sectionAlignment: properties.SectionAlignment,
                fileAlignment: properties.FileAlignment,
                imageBase: properties.BaseAddress,
                majorLinkerVersion: properties.LinkerMajorVersion,
                minorLinkerVersion: properties.LinkerMinorVersion,
                majorOperatingSystemVersion: 4,
                minorOperatingSystemVersion: 0,
                majorImageVersion: 0,
                minorImageVersion: 0,
                majorSubsystemVersion: properties.MajorSubsystemVersion,
                minorSubsystemVersion: properties.MinorSubsystemVersion,
                subsystem: properties.Subsystem,
                dllCharacteristics: properties.DllCharacteristics,
                imageCharacteristics: properties.ImageCharacteristics,
                sizeOfStackReserve: properties.SizeOfStackReserve,
                sizeOfStackCommit: properties.SizeOfStackCommit,
                sizeOfHeapReserve: properties.SizeOfHeapReserve,
                sizeOfHeapCommit: properties.SizeOfHeapCommit,
                deterministicIdProvider: isDeterministic ? new Func <BlobBuilder, ContentId>(content => ContentId.FromHash(CryptographicHashProvider.ComputeSha1(content))) : null);

            ContentId portablePdbContentId;
            if (mdWriter.EmitStandaloneDebugMetadata)
            {
                Debug.Assert(getPortablePdbStreamOpt != null);

                var debugMetadataBuilder    = new BlobBuilder();
                var debugMetadataSerializer = mdWriter.GetStandaloneDebugMetadataSerializer(metadataSerializer.MetadataSizes, debugEntryPointHandle);
                debugMetadataSerializer.SerializeMetadata(debugMetadataBuilder, peBuilder.IdProvider, out portablePdbContentId);

                // write to Portable PDB stream:
                Stream portablePdbStream = getPortablePdbStreamOpt();
                if (portablePdbStream != null)
                {
                    debugMetadataBuilder.WriteContentTo(portablePdbStream);
                }
            }
            else
            {
                portablePdbContentId = default(ContentId);
            }

            var peDirectoriesBuilder = new PEDirectoriesBuilder();

            peBuilder.AddManagedSections(
                peDirectoriesBuilder,
                metadataSerializer,
                ilBuilder,
                mappedFieldDataBuilder,
                managedResourceBuilder,
                CreateNativeResourceSectionSerializer(context.Module),
                CalculateStrongNameSignatureSize(context.Module),
                entryPointHandle,
                pdbPathOpt,
                nativePdbContentId,
                portablePdbContentId,
                properties.CorFlags);

            var       peBlob = new BlobBuilder();
            ContentId peContentId;
            peBuilder.Serialize(peBlob, peDirectoriesBuilder, out peContentId);

            // Patch MVID
            if (!mvidFixup.IsDefault)
            {
                var mvidWriter = new BlobWriter(mvidFixup);
                mvidWriter.WriteBytes(peContentId.Guid);
                Debug.Assert(mvidWriter.RemainingBytes == 0);
            }

            try
            {
                peBlob.WriteContentTo(peStream);
            }
            catch (Exception e) when(!(e is OperationCanceledException))
            {
                throw new PeWritingException(e);
            }

            return(true);
        }