code style changes

Author: methane

auth.go

@@ -228,40 +228,40 @@ func encryptPassword(password string, seed []byte, pub *rsa.PublicKey) ([]byte,
 	return rsa.EncryptOAEP(sha1, rand.Reader, pub, plain, nil)
 }
 
-// Derived from https://github.com/MariaDB/server/blob/d8e6bb00888b1f82c031938f4c8ac5d97f6874c3/plugin/auth_ed25519/ref10/sign.c
-func doEd25519Auth(scramble []byte, password string) ([]byte, error) {
+// authEd25519 does ed25519 authentication used by MariaDB.
+func authEd25519(scramble []byte, password string) ([]byte, error) {
+	// Derived from https://github.com/MariaDB/server/blob/d8e6bb00888b1f82c031938f4c8ac5d97f6874c3/plugin/auth_ed25519/ref10/sign.c
+	// Code style is from https://cs.opensource.google/go/go/+/refs/tags/go1.21.5:src/crypto/ed25519/ed25519.go;l=207
 	h := sha512.Sum512([]byte(password))
 
 	s, err := edwards25519.NewScalar().SetBytesWithClamping(h[:32])
 	if err != nil {
 		return nil, err
 	}
+	A := (&edwards25519.Point{}).ScalarBaseMult(s)
 
-	nonceHash := sha512.New()
-	nonceHash.Write(h[32:])
-	nonceHash.Write(scramble)
-	nonce := nonceHash.Sum(nil)
-
-	r, err := edwards25519.NewScalar().SetUniformBytes(nonce)
+	mh := sha512.New()
+	mh.Write(h[32:])
+	mh.Write(scramble)
+	messageDigest := mh.Sum(nil)
+	r, err := edwards25519.NewScalar().SetUniformBytes(messageDigest)
 	if err != nil {
 		return nil, err
 	}
-	R := (&edwards25519.Point{}).ScalarBaseMult(r)
 
-	A := (&edwards25519.Point{}).ScalarBaseMult(s)
-
-	kHash := sha512.New()
-	kHash.Write(R.Bytes())
-	kHash.Write(A.Bytes())
-	kHash.Write(scramble)
-	k := kHash.Sum(nil)
+	R := (&edwards25519.Point{}).ScalarBaseMult(r)
 
-	K, err := edwards25519.NewScalar().SetUniformBytes(k)
+	kh := sha512.New()
+	kh.Write(R.Bytes())
+	kh.Write(A.Bytes())
+	kh.Write(scramble)
+	hramDigest := kh.Sum(nil)
+	k, err := edwards25519.NewScalar().SetUniformBytes(hramDigest)
 	if err != nil {
 		return nil, err
 	}
 
-	S := K.MultiplyAdd(K, s, r)
+	S := k.MultiplyAdd(k, s, r)
 
 	return append(R.Bytes(), S.Bytes()...), nil
 }
@@ -335,8 +335,7 @@ func (mc *mysqlConn) auth(authData []byte, plugin string) ([]byte, error) {
 		if len(authData) != 32 {
 			return nil, ErrMalformPkt
 		}
-
-		return doEd25519Auth(authData, mc.cfg.Passwd)
+		return authEd25519(authData, mc.cfg.Passwd)
 
 	default:
 		mc.cfg.Logger.Print("unknown auth plugin:", plugin)