zip

package module
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 Go to latest Published: Mar 19, 2020 License: MIT Imports: 21 Imported by: 0

README

This fork add support for Standard Zip Encryption.

The work is based on https://github.com/alexmullins/zip

Available encryption:

zip.StandardEncryption
zip.AES128Encryption
zip.AES192Encryption
zip.AES256Encryption

Warning

Zip Standard Encryption isn't actually secure. Unless you have to work with it, please use AES encryption instead.

Example Encrypt Zip

package main

import (
	"bytes"
	"io"
	"log"
	"os"

	"github.com/yeka/zip"
)

func main() {
	contents := []byte("Hello World")
	fzip, err := os.Create(`./test.zip`)
	if err != nil {
		log.Fatalln(err)
	}
	zipw := zip.NewWriter(fzip)
	defer zipw.Close()
	w, err := zipw.Encrypt(`test.txt`, `golang`, zip.AES256Encryption)
	if err != nil {
		log.Fatal(err)
	}
	_, err = io.Copy(w, bytes.NewReader(contents))
	if err != nil {
		log.Fatal(err)
	}
	zipw.Flush()
}

Example Decrypt Zip

package main

import (
	"fmt"
	"io/ioutil"
	"log"

	"github.com/yeka/zip"
)

func main() {
	r, err := zip.OpenReader("encrypted.zip")
	if err != nil {
		log.Fatal(err)
	}
	defer r.Close()

	for _, f := range r.File {
		if f.IsEncrypted() {
			f.SetPassword("12345")
		}

		r, err := f.Open()
		if err != nil {
			log.Fatal(err)
		}

		buf, err := ioutil.ReadAll(r)
		if err != nil {
			log.Fatal(err)
		}
		defer r.Close()

		fmt.Printf("Size of %v: %v byte(s)\n", f.Name, len(buf))
	}
}

Documentation

Overview

Package zip provides support for reading and writing password protected ZIP archives.

See: http://www.pkware.com/documents/casestudies/APPNOTE.TXT

This package does not support disk spanning.

A note about ZIP64:

To be backwards compatible the FileHeader has both 32 and 64 bit Size fields. The 64 bit fields will always contain the correct value and for normal archives both fields will be the same. For files requiring the ZIP64 format the 32 bit fields will be 0xffffffff and the 64 bit fields must be used instead.

Can read/write password protected files that use Winzip's AES encryption method. See: http://www.winzip.com/aes_info.htm

Index

Examples

Constants

View Source 
const (
	Store   uint16 = 0
	Deflate uint16 = 8
)

Compression methods.

Variables

View Source 
var (
	ErrDecryption     = errors.New("zip: decryption error")
	ErrPassword       = errors.New("zip: invalid password")
	ErrAuthentication = errors.New("zip: authentication failed")
)

Encryption/Decryption Errors

View Source 
var (
	ErrFormat    = errors.New("zip: not a valid zip file")
	ErrAlgorithm = errors.New("zip: unsupported compression algorithm")
	ErrChecksum  = errors.New("zip: checksum error")
)

Functions

func RegisterCompressor 

func RegisterCompressor(method uint16, comp Compressor)

RegisterCompressor registers custom compressors for a specified method ID. The common methods Store and Deflate are built in.

func RegisterDecompressor 

func RegisterDecompressor(method uint16, d Decompressor)

RegisterDecompressor allows custom decompressors for a specified method ID.

func ZipCryptoDecryptor 

func ZipCryptoDecryptor(r *io.SectionReader, password []byte) (*io.SectionReader, error)

func ZipCryptoEncryptor 

func ZipCryptoEncryptor(i io.Writer, pass passwordFn, fw *fileWriter) (io.Writer, error)

Types

type Compressor 

type Compressor func(io.Writer) (io.WriteCloser, error)

A Compressor returns a compressing writer, writing to the provided writer. On Close, any pending data should be flushed.

type Decompressor 

type Decompressor func(io.Reader) io.ReadCloser

Decompressor is a function that wraps a Reader with a decompressing Reader. The decompressed ReadCloser is returned to callers who open files from within the archive. These callers are responsible for closing this reader when they're finished reading.

type EncryptionMethod 

type EncryptionMethod int
const (
	StandardEncryption EncryptionMethod = 1
	AES128Encryption   EncryptionMethod = 2
	AES192Encryption   EncryptionMethod = 3
	AES256Encryption   EncryptionMethod = 4
)

type File 

type File struct {
	FileHeader
	// contains filtered or unexported fields
}

func (*File) DataOffset 

func (f *File) DataOffset() (offset int64, err error)

DataOffset returns the offset of the file's possibly-compressed data, relative to the beginning of the zip file.

Most callers should instead use Open, which transparently decompresses data and verifies checksums.

func (*File) Open 

func (f *File) Open() (rc io.ReadCloser, err error)

Open returns a ReadCloser that provides access to the File's contents. Multiple files may be read concurrently.

type FileHeader 

type FileHeader struct {
	// Name is the name of the file.
	// It must be a relative path: it must not start with a drive
	// letter (e.g. C:) or leading slash, and only forward slashes
	// are allowed.
	Name string

	CreatorVersion     uint16
	ReaderVersion      uint16
	Flags              uint16
	Method             uint16
	ModifiedTime       uint16 // MS-DOS time
	ModifiedDate       uint16 // MS-DOS date
	CRC32              uint32
	CompressedSize     uint32 // Deprecated: Use CompressedSize64 instead.
	UncompressedSize   uint32 // Deprecated: Use UncompressedSize64 instead.
	CompressedSize64   uint64
	UncompressedSize64 uint64
	Extra              []byte
	ExternalAttrs      uint32 // Meaning depends on CreatorVersion
	Comment            string

	// DeferAuth being set to true will delay hmac auth/integrity
	// checks when decrypting a file meaning the reader will be
	// getting unauthenticated plaintext. It is recommended to leave
	// this set to false. For more detail:
	// https://www.imperialviolet.org/2014/06/27/streamingencryption.html
	// https://www.imperialviolet.org/2015/05/16/aeads.html
	DeferAuth bool
	// contains filtered or unexported fields
}

FileHeader describes a file within a zip file. See the zip spec for details.

func FileInfoHeader 

func FileInfoHeader(fi os.FileInfo) (*FileHeader, error)

FileInfoHeader creates a partially-populated FileHeader from an os.FileInfo. Because os.FileInfo's Name method returns only the base name of the file it describes, it may be necessary to modify the Name field of the returned header to provide the full path name of the file.

func (*FileHeader) FileInfo 

func (h *FileHeader) FileInfo() os.FileInfo

FileInfo returns an os.FileInfo for the FileHeader.

func (*FileHeader) IsEncrypted 

func (h *FileHeader) IsEncrypted() bool

IsEncrypted indicates whether this file's data is encrypted.

func (*FileHeader) ModTime 

func (h *FileHeader) ModTime() time.Time

ModTime returns the modification time in UTC. The resolution is 2s.

func (*FileHeader) Mode 

func (h *FileHeader) Mode() (mode os.FileMode)

Mode returns the permission and mode bits for the FileHeader.

func (*FileHeader) SetEncryptionMethod 

func (h *FileHeader) SetEncryptionMethod(enc EncryptionMethod)

SetEncryptionMethod sets the encryption method.

func (*FileHeader) SetModTime 

func (h *FileHeader) SetModTime(t time.Time)

SetModTime sets the ModifiedTime and ModifiedDate fields to the given time in UTC. The resolution is 2s.

func (*FileHeader) SetMode 

func (h *FileHeader) SetMode(mode os.FileMode)

SetMode changes the permission and mode bits for the FileHeader.

func (*FileHeader) SetPassword 

func (h *FileHeader) SetPassword(password string)

SetPassword sets the password used for encryption/decryption.

type ReadCloser 

type ReadCloser struct {
	Reader
	// contains filtered or unexported fields
}

func OpenReader 

func OpenReader(name string) (*ReadCloser, error)

OpenReader will open the Zip file specified by name and return a ReadCloser.

func (*ReadCloser) Close 

func (rc *ReadCloser) Close() error

Close closes the Zip file, rendering it unusable for I/O.

type Reader 

type Reader struct {
	File    []*File
	Comment string
	// contains filtered or unexported fields
}
Example 
package main

import (
	"fmt"
	"io"
	"log"
	"os"

	"github.com/yeka/zip"
)

func main() {
	// Open a zip archive for reading.
	r, err := zip.OpenReader("testdata/readme.zip")
	if err != nil {
		log.Fatal(err)
	}
	defer r.Close()

	// Iterate through the files in the archive,
	// printing some of their contents.
	for _, f := range r.File {
		fmt.Printf("Contents of %s:\n", f.Name)
		rc, err := f.Open()
		if err != nil {
			log.Fatal(err)
		}
		_, err = io.CopyN(os.Stdout, rc, 68)
		if err != nil {
			log.Fatal(err)
		}
		rc.Close()
		fmt.Println()
	}
}

Output:

Contents of README:
This is the source code repository for the Go programming language.

func NewReader 

func NewReader(r io.ReaderAt, size int64) (*Reader, error)

NewReader returns a new Reader reading from r, which is assumed to have the given size in bytes.

type Writer 

type Writer struct {
	// contains filtered or unexported fields
}

Writer implements a zip file writer.

Example 
package main

import (
	"bytes"
	"log"

	"github.com/yeka/zip"
)

func main() {
	// Create a buffer to write our archive to.
	buf := new(bytes.Buffer)

	// Create a new zip archive.
	w := zip.NewWriter(buf)

	// Add some files to the archive.
	var files = []struct {
		Name, Body string
	}{
		{"readme.txt", "This archive contains some text files."},
		{"gopher.txt", "Gopher names:\nGeorge\nGeoffrey\nGonzo"},
		{"todo.txt", "Get animal handling licence.\nWrite more examples."},
	}
	for _, file := range files {
		f, err := w.Create(file.Name)
		if err != nil {
			log.Fatal(err)
		}
		_, err = f.Write([]byte(file.Body))
		if err != nil {
			log.Fatal(err)
		}
	}

	// Make sure to check the error on Close.
	err := w.Close()
	if err != nil {
		log.Fatal(err)
	}
}

Output:

func NewWriter 

func NewWriter(w io.Writer) *Writer

NewWriter returns a new Writer writing a zip file to w.

func (*Writer) Close 

func (w *Writer) Close() error

Close finishes writing the zip file by writing the central directory. It does not (and can not) close the underlying writer.

func (*Writer) Create 

func (w *Writer) Create(name string) (io.Writer, error)

Create adds a file to the zip file using the provided name. It returns a Writer to which the file contents should be written. The name must be a relative path: it must not start with a drive letter (e.g. C:) or leading slash, and only forward slashes are allowed. The file's contents must be written to the io.Writer before the next call to Create, CreateHeader, or Close.

func (*Writer) CreateHeader 

func (w *Writer) CreateHeader(fh *FileHeader) (io.Writer, error)

CreateHeader adds a file to the zip file using the provided FileHeader for the file metadata. It returns a Writer to which the file contents should be written.

The file's contents must be written to the io.Writer before the next call to Create, CreateHeader, or Close. The provided FileHeader fh must not be modified after a call to CreateHeader.

func (*Writer) Encrypt 

func (w *Writer) Encrypt(name string, password string, enc EncryptionMethod) (io.Writer, error)

Encrypt adds a file to the zip file using the provided name. It returns a Writer to which the file contents should be written. File contents will be encrypted with AES-256 using the given password. The file's contents must be written to the io.Writer before the next call to Create, CreateHeader, or Close.

Example 
package main

import (
	"bytes"
	"io"
	"log"
	"os"

	"github.com/yeka/zip"
)

func main() {
	contents := []byte("Hello World")

	// write a password zip
	raw := new(bytes.Buffer)
	zipw := zip.NewWriter(raw)
	w, err := zipw.Encrypt("hello.txt", "golang", zip.AES256Encryption)
	if err != nil {
		log.Fatal(err)
	}
	_, err = io.Copy(w, bytes.NewReader(contents))
	if err != nil {
		log.Fatal(err)
	}
	zipw.Close()

	// read the password zip
	zipr, err := zip.NewReader(bytes.NewReader(raw.Bytes()), int64(raw.Len()))
	if err != nil {
		log.Fatal(err)
	}
	for _, z := range zipr.File {
		z.SetPassword("golang")
		rr, err := z.Open()
		if err != nil {
			log.Fatal(err)
		}
		_, err = io.Copy(os.Stdout, rr)
		if err != nil {
			log.Fatal(err)
		}
		rr.Close()
	}
}

Output:

Hello World

func (*Writer) Flush 

func (w *Writer) Flush() error

Flush flushes any buffered data to the underlying writer. Calling Flush is not normally necessary; calling Close is sufficient.

func (*Writer) SetOffset 

func (w *Writer) SetOffset(n int64)

SetOffset sets the offset of the beginning of the zip data within the underlying writer. It should be used when the zip data is appended to an existing file, such as a binary executable. It must be called before any data is written.

type ZipCrypto 

type ZipCrypto struct {
	Keys [3]uint32
	// contains filtered or unexported fields
}

func NewZipCrypto 

func NewZipCrypto(passphrase []byte) *ZipCrypto

func (*ZipCrypto) Decrypt 

func (z *ZipCrypto) Decrypt(chiper []byte) []byte

func (*ZipCrypto) Encrypt 

func (z *ZipCrypto) Encrypt(data []byte) []byte

Source Files

View all Source files

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