zip.go

// Copyright 2019 Torben Schinke
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package main

import (
	"archive/zip"
	"fmt"
	"io"
	"os"
	"path/filepath"
	"strings"
)

// Unzip will decompress a zip archive
func Unzip(src string, dest string) error {

	r, err := zip.OpenReader(src)
	if err != nil {
		return err
	}
	defer r.Close()

	for _, f := range r.File {

		// Store filename/path for returning and using later on
		fpath := filepath.Join(dest, f.Name)

		// Check for ZipSlip. More Info: http://bit.ly/2MsjAWE
		if !strings.HasPrefix(fpath, filepath.Clean(dest)+string(os.PathSeparator)) {
			return fmt.Errorf("%s: illegal file path", fpath)
		}

		if f.FileInfo().IsDir() {
			// Make Folder
			err = os.MkdirAll(fpath, os.ModePerm)
			if err != nil {
				return err
			}
			continue
		}

		// Make File
		if err = os.MkdirAll(filepath.Dir(fpath), os.ModePerm); err != nil {
			return err
		}

		outFile, err := os.OpenFile(fpath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, f.Mode())
		if err != nil {
			return err
		}

		rc, err := f.Open()
		if err != nil {
			return err
		}

		_, err = io.Copy(outFile, rc)

		// Close the file without defer to close before next iteration of loop
		_ = outFile.Close()
		_ = rc.Close()

		if err != nil {
			return err
		}
	}
	return nil
}