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Reduced size of Windows executables

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This commit is contained in:
Eduard Urbach 2024-08-16 11:38:48 +02:00
parent ca3d0ee2e8
commit 1255146794
Signed by: eduard
GPG key ID: 49226B848C78F6C8
2 changed files with 33 additions and 30 deletions
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56
src/exe/pe/EXE.go
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@ -24,7 +24,7 @@ type DLL struct {
// Write writes the EXE file to the given writer.
func Write(writer io.Writer, code []byte, data []byte) {
NumSections := 3
NumSections := 2
HeaderEnd := DOSHeaderSize + NTHeaderSize + OptionalHeader64Size + SectionHeaderSize*NumSections
codeStart, codePadding := exe.Align(HeaderEnd, config.Align)
dataStart, dataPadding := exe.Align(codeStart+len(code), config.Align)
@ -61,29 +61,36 @@ func Write(writer io.Writer, code []byte, data []byte) {
}
dllAddresses = append(dllAddresses, 0)
importStart, importPadding := exe.Align(dataStart+len(data), config.Align)
itblSize := DLLImportSize*len(dlls) + DLLImportSize
iatblSize := 8 * len(dllAddresses)
itblStart := importStart
iatblStart := itblStart + itblSize
// Add the address table to the data section
functionAddressesStart := dataStart + len(data)
functionAddressesSize := 8 * len(dllAddresses)
data, err := binary.Append(data, binary.LittleEndian, &dllAddresses)
if err != nil {
panic(err)
}
dllImports = append(dllImports, DLLImport{
RvaFunctionNameList: uint32(iatblStart),
RvaFunctionNameList: uint32(functionAddressesStart),
TimeDateStamp: 0,
ForwarderChain: 0,
RvaModuleName: uint32(dataStart + dllName),
RvaFunctionAddressList: uint32(iatblStart),
RvaFunctionAddressList: uint32(functionAddressesStart),
})
dllImports = append(dllImports, DLLImport{
RvaFunctionNameList: 0,
TimeDateStamp: 0,
ForwarderChain: 0,
RvaModuleName: 0, // must be zero
RvaFunctionAddressList: 0,
})
dllImports = append(dllImports, DLLImport{}) // a zeroed structure marks the end of the list
imageSize := iatblStart + iatblSize
// Add imports to the data section
importsStart := dataStart + len(data)
importsSize := DLLImportSize * len(dllImports)
data, err = binary.Append(data, binary.LittleEndian, &dllImports)
if err != nil {
panic(err)
}
imageSize := functionAddressesStart + functionAddressesSize
imageSize, _ = exe.Align(imageSize, config.Align)
pe := &EXE{
@ -102,7 +109,7 @@ func Write(writer io.Writer, code []byte, data []byte) {
Characteristics: IMAGE_FILE_EXECUTABLE_IMAGE | IMAGE_FILE_LARGE_ADDRESS_AWARE,
},
OptionalHeader64: OptionalHeader64{
Magic: 0x020B, // PE32+ executable
Magic: 0x020B, // PE32+ / 64-bit executable
MajorLinkerVersion: 0x0E,
MinorLinkerVersion: 0x16,
SizeOfCode: uint32(len(code)),
@ -133,7 +140,7 @@ func Write(writer io.Writer, code []byte, data []byte) {
NumberOfRvaAndSizes: 16,
DataDirectory: [16]DataDirectory{
{VirtualAddress: 0, Size: 0},
{VirtualAddress: uint32(itblStart), Size: uint32(itblSize)}, // RVA of the imported function table
{VirtualAddress: uint32(importsStart), Size: uint32(importsSize)}, // RVA of the imported function table
{VirtualAddress: 0, Size: 0},
{VirtualAddress: 0, Size: 0},
{VirtualAddress: 0, Size: 0},
@ -144,7 +151,7 @@ func Write(writer io.Writer, code []byte, data []byte) {
{VirtualAddress: 0, Size: 0},
{VirtualAddress: 0, Size: 0},
{VirtualAddress: 0, Size: 0},
{VirtualAddress: uint32(iatblStart), Size: uint32(iatblSize)}, // RVA of the import address table
{VirtualAddress: uint32(functionAddressesStart), Size: uint32(functionAddressesSize)}, // RVA of the import address table
{VirtualAddress: 0, Size: 0},
{VirtualAddress: 0, Size: 0},
{VirtualAddress: 0, Size: 0},
@ -167,14 +174,6 @@ func Write(writer io.Writer, code []byte, data []byte) {
RawAddress: uint32(dataStart),
Characteristics: IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ,
},
{
Name: [8]byte{'.', 'i', 'd', 'a', 't', 'a'},
VirtualSize: uint32(iatblSize + itblSize),
VirtualAddress: uint32(importStart),
RawSize: uint32(iatblSize + itblSize),
RawAddress: uint32(importStart),
Characteristics: IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE,
},
},
}
@ -187,7 +186,4 @@ func Write(writer io.Writer, code []byte, data []byte) {
writer.Write(code)
writer.Write(bytes.Repeat([]byte{0x00}, int(dataPadding)))
writer.Write(data)
writer.Write(bytes.Repeat([]byte{0x00}, int(importPadding)))
binary.Write(writer, binary.LittleEndian, &dllImports)
binary.Write(writer, binary.LittleEndian, &dllAddresses)
}