forked from cadey/xesite
143 lines
3.4 KiB
Go
143 lines
3.4 KiB
Go
// Package zipexe attempts to open an executable binary file as a zip file.
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package zipexe
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import (
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"archive/zip"
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"debug/elf"
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"debug/macho"
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"debug/pe"
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"errors"
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"io"
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"os"
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)
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// Opens a zip file by path.
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func Open(path string) (*zip.Reader, error) {
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_, rd, err := OpenCloser(path)
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return rd, err
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}
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// OpenCloser is like Open but returns an additional Closer to avoid leaking open files.
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func OpenCloser(path string) (io.Closer, *zip.Reader, error) {
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file, err := os.Open(path)
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if err != nil {
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return nil, nil, err
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}
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finfo, err := file.Stat()
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if err != nil {
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return nil, nil, err
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}
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zr, err := NewReader(file, finfo.Size())
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if err != nil {
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return nil, nil, err
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}
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return file, zr, nil
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}
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// Open a zip file, specially handling various binaries that may have been
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// augmented with zip data.
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func NewReader(rda io.ReaderAt, size int64) (*zip.Reader, error) {
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handlers := []func(io.ReaderAt, int64) (*zip.Reader, error){
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zip.NewReader,
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zipExeReaderMacho,
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zipExeReaderElf,
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zipExeReaderPe,
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}
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for _, handler := range handlers {
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zfile, err := handler(rda, size)
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if err == nil {
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return zfile, nil
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}
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}
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return nil, errors.New("Couldn't Open As Executable")
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}
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// zipExeReaderMacho treats the file as a Mach-O binary
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// (Mac OS X / Darwin executable) and attempts to find a zip archive.
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func zipExeReaderMacho(rda io.ReaderAt, size int64) (*zip.Reader, error) {
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file, err := macho.NewFile(rda)
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if err != nil {
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return nil, err
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}
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var max int64
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for _, load := range file.Loads {
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seg, ok := load.(*macho.Segment)
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if ok {
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// Check if the segment contains a zip file
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if zfile, err := zip.NewReader(seg, int64(seg.Filesz)); err == nil {
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return zfile, nil
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}
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// Otherwise move end of file pointer
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end := int64(seg.Offset + seg.Filesz)
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if end > max {
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max = end
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}
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}
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}
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// No zip file within binary, try appended to end
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section := io.NewSectionReader(rda, max, size-max)
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return zip.NewReader(section, section.Size())
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}
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// zipExeReaderPe treats the file as a Portable Exectuable binary
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// (Windows executable) and attempts to find a zip archive.
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func zipExeReaderPe(rda io.ReaderAt, size int64) (*zip.Reader, error) {
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file, err := pe.NewFile(rda)
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if err != nil {
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return nil, err
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}
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var max int64
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for _, sec := range file.Sections {
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// Check if this section has a zip file
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if zfile, err := zip.NewReader(sec, int64(sec.Size)); err == nil {
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return zfile, nil
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}
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// Otherwise move end of file pointer
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end := int64(sec.Offset + sec.Size)
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if end > max {
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max = end
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}
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}
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// No zip file within binary, try appended to end
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section := io.NewSectionReader(rda, max, size-max)
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return zip.NewReader(section, section.Size())
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}
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// zipExeReaderElf treats the file as a ELF binary
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// (linux/BSD/etc... executable) and attempts to find a zip archive.
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func zipExeReaderElf(rda io.ReaderAt, size int64) (*zip.Reader, error) {
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file, err := elf.NewFile(rda)
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if err != nil {
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return nil, err
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}
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var max int64
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for _, sect := range file.Sections {
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if sect.Type == elf.SHT_NOBITS {
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continue
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}
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// Check if this section has a zip file
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if zfile, err := zip.NewReader(sect, int64(sect.Size)); err == nil {
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return zfile, nil
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}
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// Otherwise move end of file pointer
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end := int64(sect.Offset + sect.Size)
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if end > max {
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max = end
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}
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}
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// No zip file within binary, try appended to end
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section := io.NewSectionReader(rda, max, size-max)
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return zip.NewReader(section, section.Size())
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}
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