next-eeze.git

ref: b8662330e5a2aed7af1568e6cddb044597857f5c

fs/fs.go


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package fs

import (
	"notabug.org/apiote/next-eeze/password"

	"crypto/aes"
	"crypto/cipher"
	"crypto/rand"
	"errors"
	"io"
	"io/ioutil"
	"log"
	"os"
	"os/user"
	"path/filepath"

	"golang.org/x/crypto/argon2"

	"git.sr.ht/~sircmpwn/go-bare"
)

type EncryptedContent struct {
	Salt       []byte
	CipherText []byte
}

type Credentials struct {
	Server   string
	Username string
	Password string
}

func getDataLocation() string {
	usr, _ := user.Current()
	dir := usr.HomeDir
	path := filepath.Join(dir, "/.local/share/next-eeze/")
	return path
}

// todo memguard passwords, masterPassword
func SaveBare(passwords []password.BarePassword, masterPassword string) error {
	salt := makeSalt()
	// todo memguard
	key := deriveKey(masterPassword, salt)
	result, err := os.Create(getDataLocation() + "/passwords.bare")
	if err != nil {
		log.Fatal("Error creating passwords file. ", err)
		return err
	}
	defer result.Close()
	// todo memguard
	bytes, err := bare.Marshal(&passwords)
	if err != nil {
		log.Fatal("Error marshalling passwords. ", err)
		return err
	}
	cipherText, err := encrypt(bytes, key)
	if err != nil {
		log.Fatal("Error encrypting credentials. ", err)
		return err
	}

	enc := EncryptedContent{
		Salt:       salt,
		CipherText: cipherText,
	}
	bytes, err = bare.Marshal(&enc)
	if err != nil {
		log.Fatal("Error marshalling encrypted credentials. ", err)
		return err
	}
	_, err = result.Write(bytes)
	if err != nil {
		log.Fatal("Error writing to file. ", err)
		return err
	}
	_, err = result.Write(bytes)
	if err != nil {
		log.Fatal("Error writing to file. ", err)
		return err
	}
	return nil
}

// todo memguard passwords, masterPassword
func Save(passwords []password.NextPassword, masterPassword string) error {
	// todo memguard
	barePasswords := []password.BarePassword{}
	// todo memguard
	for _, p := range passwords {
		barePasswords = append(barePasswords, p.ToBarePassword())
	}
	err := SaveBare(barePasswords, masterPassword)
	return err
}

// todo memguard masterPassword
func Read(masterPassword string) ([]password.BarePassword, error) {
	enc := EncryptedContent{}
	// todo memguard
	passwords := []password.BarePassword{}
	content, err := ioutil.ReadFile(getDataLocation() + "/passwords.bare")
	if err != nil {
		log.Fatal("Error reading to file. ", err)
		return nil, err
	}
	err = bare.Unmarshal(content, &enc)
	if err != nil {
		log.Fatal("Error unmarshalling encrypted. ", err)
		return passwords, err
	}
	// todo memguard
	key := deriveKey(masterPassword, enc.Salt)
	// todo memguard
	plaintext, err := decrypt(enc.CipherText, key)
	if err != nil {
		log.Fatal("Error decrypting passwords. ", err)
		return passwords, err
	}
	err = bare.Unmarshal(plaintext, &passwords)
	if err != nil {
		log.Fatal("Error unmarshalling. ", err)
		return nil, err
	}
	return passwords, nil
}

// todo memguard credentials, masterPassword
func SaveCredentials(credentials Credentials, masterPassword string) error {
	salt := makeSalt()
	// todo memguard
	key := deriveKey(masterPassword, salt)

	result, err := os.Create(getDataLocation() + "/credentials.bare")
	if err != nil {
		log.Fatal("Error creating credentials file. ", err)
		return err
	}
	defer result.Close()
	// todo memguard
	bytes, err := bare.Marshal(&credentials)
	if err != nil {
		log.Fatal("Error marshalling credentials. ", err)
		return err
	}
	cipherText, err := encrypt(bytes, key)
	if err != nil {
		log.Fatal("Error encrypting credentials. ", err)
		return err
	}

	enc := EncryptedContent{
		Salt:       salt,
		CipherText: cipherText,
	}
	bytes, err = bare.Marshal(&enc)
	if err != nil {
		log.Fatal("Error marshalling encrypted credentials. ", err)
		return err
	}
	_, err = result.Write(bytes)
	if err != nil {
		log.Fatal("Error writing to file. ", err)
		return err
	}
	return nil
}

// todo memguard masterPassword
func ReadCredentials(masterPassword string) (Credentials, error) {
	enc := EncryptedContent{}
	// todo memguard
	credentials := Credentials{}
	content, err := ioutil.ReadFile(getDataLocation() + "/credentials.bare")
	if err != nil {
		log.Fatal("Error reading to file. ", err)
		return credentials, err
	}
	err = bare.Unmarshal(content, &enc)
	if err != nil {
		log.Fatal("Error unmarshalling encrypted. ", err)
		return credentials, err
	}
	// todo memguard
	key := deriveKey(masterPassword, enc.Salt)
	// todo memguard
	plaintext, err := decrypt(enc.CipherText, key)
	if err != nil {
		log.Fatal("Error decrypting credentials. ", err)
		return credentials, err
	}
	err = bare.Unmarshal(plaintext, &credentials)
	return credentials, nil
}

func makeSalt() []byte {
	key := [32]byte{}
	_, err := io.ReadFull(rand.Reader, key[:])
	if err != nil {
		panic(err)
	}
	return key[:]
}

// todo memguard password
func deriveKey(password string, salt []byte) [32]byte {
	// todo memguard
	key := argon2.IDKey([]byte(password), salt, 1, 64*1024, 4, 32)
	// todo memguard
	var keyArr [32]byte
	copy(keyArr[:], key)
	return keyArr
}

// todo memguard plaintext, key
func encrypt(plaintext []byte, key [32]byte) (ciphertext []byte, err error) {
	block, err := aes.NewCipher(key[:])
	if err != nil {
		return nil, err
	}

	gcm, err := cipher.NewGCM(block)
	if err != nil {
		return nil, err
	}

	nonce := make([]byte, gcm.NonceSize())
	_, err = io.ReadFull(rand.Reader, nonce)
	if err != nil {
		return nil, err
	}

	return gcm.Seal(nonce, nonce, plaintext, nil), nil
}

// todo memguard key
func decrypt(ciphertext []byte, key [32]byte) (plaintext []byte, err error) {
	block, err := aes.NewCipher(key[:])
	if err != nil {
		return nil, err
	}

	gcm, err := cipher.NewGCM(block)
	if err != nil {
		return nil, err
	}

	if len(ciphertext) < gcm.NonceSize() {
		return nil, errors.New("malformed ciphertext")
	}

	return gcm.Open(nil,
		ciphertext[:gcm.NonceSize()],
		ciphertext[gcm.NonceSize():],
		nil,
	)
}