addSecret.go

/*
Copyright © 2019 NAME HERE <EMAIL ADDRESS>

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

    http://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 cmd

import (
	"bytes"
	"context"
	"crypto/aes"
	"crypto/cipher"
	"crypto/rand"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"io"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"strings"

	"github.com/spf13/cobra"
	"golang.org/x/oauth2"
	"golang.org/x/oauth2/google"
	"google.golang.org/api/drive/v3"
)

// addSecretCmd represents the addSecret command
var addSecretCmd = &cobra.Command{
	Use:   "addSecret",
	Short: "A brief description of your command",
	Long: `A longer description that spans multiple lines and likely contains examples
and usage of using your command. For example:

Cobra is a CLI library for Go that empowers applications.
This application is a tool to generate the needed files
to quickly create a Cobra application.`,
	Run: func(cmd *cobra.Command, args []string) {
		fmt.Println("addSecret called")
		doTheThing()
	},
}

func init() {
	rootCmd.AddCommand(addSecretCmd)

	// Here you will define your flags and configuration settings.

	// Cobra supports Persistent Flags which will work for this command
	// and all subcommands, e.g.:
	// addSecretCmd.PersistentFlags().String("foo", "", "A help for foo")

	// Cobra supports local flags which will only run when this command
	// is called directly, e.g.:
	// addSecretCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")
}

func padByteArrayForEncryption(byteArray []byte) []byte {
	if len(byteArray)%aes.BlockSize != 0 {
		return append(byteArray, make([]byte, aes.BlockSize-(len(byteArray)%aes.BlockSize))...)
	} else {
		return byteArray
	}
}

func ExampleNewCBCEncrypter(plaintext_string string) string {
	// Load your secret key from a safe place and reuse it across multiple
	// NewCipher calls. (Obviously don't use this example key for anything
	// real.) If you want to convert a passphrase to a key, use a suitable
	// package like bcrypt or scrypt.
	key, _ := hex.DecodeString("6368616e676520746869732070617373")
	plaintext := []byte(plaintext_string)

	// CBC mode works on blocks so plaintexts may need to be padded to the
	// next whole block. For an example of such padding, see
	// https://tools.ietf.org/html/rfc5246#section-6.2.3.2. Here we'll
	// assume that the plaintext is already of the correct length.
	plaintext = padByteArrayForEncryption(plaintext)

	block, err := aes.NewCipher(key)
	if err != nil {
		panic(err)
	}

	// The IV needs to be unique, but not secure. Therefore it's common to
	// include it at the beginning of the ciphertext.
	ciphertext := make([]byte, aes.BlockSize+len(plaintext))
	iv := ciphertext[:aes.BlockSize]
	if _, err := io.ReadFull(rand.Reader, iv); err != nil {
		panic(err)
	}

	mode := cipher.NewCBCEncrypter(block, iv)
	mode.CryptBlocks(ciphertext[aes.BlockSize:], plaintext)

	// It's important to remember that ciphertexts must be authenticated
	// (i.e. by using crypto/hmac) as well as being encrypted in order to
	// be secure.

	return string(ciphertext)
}

func ExampleNewCBCDecrypter(ciphertext_string string) string {
	// Load your secret key from a safe place and reuse it across multiple
	// NewCipher calls. (Obviously don't use this example key for anything
	// real.) If you want to convert a passphrase to a key, use a suitable
	// package like bcrypt or scrypt.
	key, _ := hex.DecodeString("6368616e676520746869732070617373")
	ciphertext := []byte(ciphertext_string)

	block, err := aes.NewCipher(key)
	if err != nil {
		panic(err)
	}

	// The IV needs to be unique, but not secure. Therefore it's common to
	// include it at the beginning of the ciphertext.
	if len(ciphertext) < aes.BlockSize {
		panic("ciphertext too short")
	}
	iv := ciphertext[:aes.BlockSize]
	ciphertext = ciphertext[aes.BlockSize:]

	// CBC mode always works in whole blocks.
	if len(ciphertext)%aes.BlockSize != 0 {
		panic("ciphertext is not a multiple of the block size")
	}

	mode := cipher.NewCBCDecrypter(block, iv)

	// CryptBlocks can work in-place if the two arguments are the same.
	mode.CryptBlocks(ciphertext, ciphertext)

	// If the original plaintext lengths are not a multiple of the block
	// size, padding would have to be added when encrypting, which would be
	// removed at this point. For an example, see
	// https://tools.ietf.org/html/rfc5246#section-6.2.3.2. However, it's
	// critical to note that ciphertexts must be authenticated (i.e. by
	// using crypto/hmac) before being decrypted in order to avoid creating
	// a padding oracle.

	// Output: exampleplaintext
	return string(ciphertext)
}

// Retrieve a token, saves the token, then returns the generated client.
func getClient(config *oauth2.Config) *http.Client {
	// The file token.json stores the user's access and refresh tokens, and is
	// created automatically when the authorization flow completes for the first
	// time.
	tokFile := "token.json"
	tok, err := tokenFromFile(tokFile)
	if err != nil {
		tok = getTokenFromWeb(config)
		saveToken(tokFile, tok)
	}
	return config.Client(context.Background(), tok)
}

// Request a token from the web, then returns the retrieved token.
func getTokenFromWeb(config *oauth2.Config) *oauth2.Token {
	authURL := config.AuthCodeURL("state-token", oauth2.AccessTypeOffline)
	fmt.Printf("Go to the following link in your browser then type the "+
		"authorization code: \n%v\n", authURL)

	var authCode string
	if _, err := fmt.Scan(&authCode); err != nil {
		log.Fatalf("Unable to read authorization code %v", err)
	}

	tok, err := config.Exchange(context.TODO(), authCode)
	if err != nil {
		log.Fatalf("Unable to retrieve token from web %v", err)
	}
	return tok
}

// Retrieves a token from a local file.
func tokenFromFile(file string) (*oauth2.Token, error) {
	f, err := os.Open(file)
	if err != nil {
		return nil, err
	}
	defer f.Close()
	tok := &oauth2.Token{}
	err = json.NewDecoder(f).Decode(tok)
	return tok, err
}

// Saves a token to a file path.
func saveToken(path string, token *oauth2.Token) {
	fmt.Printf("Saving credential file to: %s\n", path)
	f, err := os.OpenFile(path, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
	if err != nil {
		log.Fatalf("Unable to cache oauth token: %v", err)
	}
	defer f.Close()
	json.NewEncoder(f).Encode(token)
}

func doTheThing() {
	b, err := ioutil.ReadFile("credentials.json")
	if err != nil {
		log.Fatalf("Unable to read client secret file: %v", err)
	}

	// If modifying these scopes, delete your previously saved token.json.
	config, err := google.ConfigFromJSON(b, drive.DriveScope)
	if err != nil {
		log.Fatalf("Unable to parse client secret file to config: %v", err)
	}
	client := getClient(config)

	srv, err := drive.New(client)
	if err != nil {
		log.Fatalf("Unable to retrieve Drive client: %v", err)
	}

	fileListResult, err := srv.Files.List().Q("name = 'hi.txt'").Do()
	if err != nil {
		log.Fatalf("Unable to list files: %v", err)
	}

	var f *drive.File

	if len(fileListResult.Files) > 0 {
		fmt.Printf("File already exists\n")
		f = fileListResult.Files[0]
	} else {
		fmt.Printf("No file found. Creating new file.\n")
		f, err = srv.Files.Create(&drive.File{Name: "hi.txt"}).Media(strings.NewReader(ExampleNewCBCEncrypter("{\"test\": \"this\"}"))).Do()
		if err != nil {
			log.Fatalf("Unable to create file: %v", err)
		}
	}

	response, err := srv.Files.Get(f.Id).Download()
	defer response.Body.Close()
	body, err := ioutil.ReadAll(response.Body)

	decrypted_body := ExampleNewCBCDecrypter(string(body))

	var result map[string]interface{}

	err = json.Unmarshal([]byte(decrypted_body), &result)
	if err != nil {
		log.Fatalf("%v", err)
	}

	var prettyJSON bytes.Buffer

	json.Indent(&prettyJSON, []byte(decrypted_body), "", "  ")

	fmt.Printf("%s\n", prettyJSON.Bytes())

	fmt.Printf("New File:\n%s (%s)\n", f.Name, f.Id)

	fmt.Printf("Encrypted File:\n%s\nDecrypted File:\n%s\n", string(body), decrypted_body)

	// fmt.Printf("File Contents:\n%s\nDecrypted File Contents:\n%s\n", )

	// f2, err := srv.Files.Get("17egyyWcY2a5gm--bKv_JP4dzRXwhipsm").Do()

	// fmt.Printf("Created File:\n%s (%s)\n", f2.Name, f2.Id)

	// r, err := srv.Files.List().
	// 	Fields("nextPageToken, files(id, name)").Do()
	// if err != nil {
	// 	log.Fatalf("Unable to retrieve files: %v", err)
	// }
	// fmt.Println("Files:")
	// if len(r.Files) == 0 {
	// 	fmt.Println("No files found.")
	// } else {
	// 	for _, i := range r.Files {
	// 		fmt.Printf("%s (%s)\n", i.Name, i.Id)
	// 	}
	// }
}