123 lines
3.2 KiB
Go
123 lines
3.2 KiB
Go
package secure
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import (
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"crypto/hmac"
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"crypto/rand"
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"crypto/sha256"
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"crypto/subtle"
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"encoding/base64"
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"errors"
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"fmt"
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"os"
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"strings"
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"golang.org/x/crypto/argon2"
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"golang.org/x/crypto/chacha20poly1305"
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)
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const (
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argonMemory = 64 * 1024
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argonTime = 3
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argonThreads = 2
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argonKeyLen = 32
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)
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type Cipher struct {
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key []byte
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}
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func LoadCipher(path string) (*Cipher, error) {
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raw, err := os.ReadFile(path)
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if err != nil {
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return nil, fmt.Errorf("read master key: %w", err)
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}
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raw = []byte(strings.TrimSpace(string(raw)))
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key, err := base64.RawStdEncoding.DecodeString(string(raw))
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if err != nil {
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key, err = base64.StdEncoding.DecodeString(string(raw))
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}
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if err != nil || len(key) != chacha20poly1305.KeySize {
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return nil, errors.New("master key must be a base64-encoded 32-byte value")
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}
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return &Cipher{key: key}, nil
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}
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func (c *Cipher) Encrypt(plaintext string) (ciphertext, nonce []byte, err error) {
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aead, err := chacha20poly1305.NewX(c.key)
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if err != nil {
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return nil, nil, err
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}
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nonce = make([]byte, chacha20poly1305.NonceSizeX)
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if _, err = rand.Read(nonce); err != nil {
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return nil, nil, fmt.Errorf("create encryption nonce: %w", err)
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}
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return aead.Seal(nil, nonce, []byte(plaintext), nil), nonce, nil
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}
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func (c *Cipher) Decrypt(ciphertext, nonce []byte) (string, error) {
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aead, err := chacha20poly1305.NewX(c.key)
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if err != nil {
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return "", err
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}
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plaintext, err := aead.Open(nil, nonce, ciphertext, nil)
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if err != nil {
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return "", errors.New("could not decrypt stored credential")
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}
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return string(plaintext), nil
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}
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func (c *Cipher) Fingerprint(value string) string {
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mac := hmac.New(sha256.New, c.key)
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_, _ = mac.Write([]byte(value))
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return base64.RawURLEncoding.EncodeToString(mac.Sum(nil))
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}
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func RandomToken(bytes int) (string, error) {
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buf := make([]byte, bytes)
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if _, err := rand.Read(buf); err != nil {
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return "", err
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}
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return base64.RawURLEncoding.EncodeToString(buf), nil
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}
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func HashToken(token string) string {
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sum := sha256.Sum256([]byte(token))
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return base64.RawURLEncoding.EncodeToString(sum[:])
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}
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func HashPassword(password string) (string, error) {
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if len(password) < 12 {
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return "", errors.New("password must contain at least 12 characters")
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}
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salt := make([]byte, 16)
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if _, err := rand.Read(salt); err != nil {
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return "", err
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}
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hash := argon2.IDKey([]byte(password), salt, argonTime, argonMemory, argonThreads, argonKeyLen)
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return fmt.Sprintf("argon2id$v=19$m=%d,t=%d,p=%d$%s$%s", argonMemory, argonTime, argonThreads,
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base64.RawStdEncoding.EncodeToString(salt), base64.RawStdEncoding.EncodeToString(hash)), nil
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}
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func VerifyPassword(encoded, password string) bool {
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parts := strings.Split(encoded, "$")
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if len(parts) != 5 || parts[0] != "argon2id" || parts[1] != "v=19" {
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return false
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}
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var memory uint32
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var iterations uint32
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var threads uint8
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if _, err := fmt.Sscanf(parts[2], "m=%d,t=%d,p=%d", &memory, &iterations, &threads); err != nil {
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return false
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}
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salt, err := base64.RawStdEncoding.DecodeString(parts[3])
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if err != nil {
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return false
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}
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want, err := base64.RawStdEncoding.DecodeString(parts[4])
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if err != nil {
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return false
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}
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got := argon2.IDKey([]byte(password), salt, iterations, memory, threads, uint32(len(want)))
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return subtle.ConstantTimeCompare(got, want) == 1
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}
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