add support for MariaDB ED25519 plugin (#998)

Co-authored-by: Gusted <postmaster@gusted.xyz>>
Co-authored-by: lance6716 <lance6716@gmail.com>

Author: 3 people

client/auth.go

@@ -15,7 +15,7 @@ import (
 const defaultAuthPluginName = mysql.AUTH_NATIVE_PASSWORD
 
 // defines the supported auth plugins
-var supportedAuthPlugins = []string{mysql.AUTH_NATIVE_PASSWORD, mysql.AUTH_SHA256_PASSWORD, mysql.AUTH_CACHING_SHA2_PASSWORD}
+var supportedAuthPlugins = []string{mysql.AUTH_NATIVE_PASSWORD, mysql.AUTH_SHA256_PASSWORD, mysql.AUTH_CACHING_SHA2_PASSWORD, mysql.AUTH_MARIADB_ED25519}
 
 // helper function to determine what auth methods are allowed by this client
 func authPluginAllowed(pluginName string) bool {
@@ -172,6 +172,15 @@ func (c *Conn) genAuthResponse(authData []byte) ([]byte, bool, error) {
 			// see: https://dev.mysql.com/doc/internals/en/public-key-retrieval.html
 			return []byte{1}, false, nil
 		}
+	case mysql.AUTH_MARIADB_ED25519:
+		if len(authData) != 32 {
+			return nil, false, mysql.ErrMalformPacket
+		}
+		res, err := mysql.CalcEd25519Password(authData, c.password)
+		if err != nil {
+			return nil, false, err
+		}
+		return res, false, nil
 	default:
 		// not reachable
 		return nil, false, fmt.Errorf("auth plugin '%s' is not supported", c.authPluginName)
@@ -195,7 +204,7 @@ func (c *Conn) genAttributes() []byte {
 // See: http://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::HandshakeResponse
 func (c *Conn) writeAuthHandshake() error {
 	if !authPluginAllowed(c.authPluginName) {
-		return fmt.Errorf("unknow auth plugin name '%s'", c.authPluginName)
+		return fmt.Errorf("unknown auth plugin name '%s'", c.authPluginName)
 	}
 
 	// Set default client capabilities that reflect the abilities of this library

go.mod

@@ -20,6 +20,7 @@ require (
 )
 
 require (
+	filippo.io/edwards25519 v1.1.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/kr/pretty v0.3.1 // indirect
 	github.com/pingcap/failpoint v0.0.0-20240528011301-b51a646c7c86 // indirect

go.sum

@@ -1,3 +1,5 @@
+filippo.io/edwards25519 v1.1.0 h1:FNf4tywRC1HmFuKW5xopWpigGjJKiJSV0Cqo0cJWDaA=
+filippo.io/edwards25519 v1.1.0/go.mod h1:BxyFTGdWcka3PhytdK4V28tE5sGfRvvvRV7EaN4VDT4=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/BurntSushi/toml v1.3.2 h1:o7IhLm0Msx3BaB+n3Ag7L8EVlByGnpq14C4YWiu/gL8=
 github.com/BurntSushi/toml v1.3.2/go.mod h1:CxXYINrC8qIiEnFrOxCa7Jy5BFHlXnUU2pbicEuybxQ=

mysql/const.go

@@ -24,6 +24,7 @@ const (
 	AUTH_CLEAR_PASSWORD        = "mysql_clear_password"
 	AUTH_CACHING_SHA2_PASSWORD = "caching_sha2_password"
 	AUTH_SHA256_PASSWORD       = "sha256_password"
+	AUTH_MARIADB_ED25519       = "client_ed25519"
 )
 
 // SERVER_STATUS_flags_enum

mysql/util.go

@@ -7,6 +7,7 @@ import (
 	"crypto/rsa"
 	"crypto/sha1"
 	"crypto/sha256"
+	"crypto/sha512"
 	"encoding/binary"
 	"fmt"
 	"io"
@@ -15,6 +16,7 @@ import (
 	"strings"
 	"time"
 
+	"filippo.io/edwards25519"
 	"github.com/Masterminds/semver"
 	"github.com/go-mysql-org/go-mysql/utils"
 	"github.com/pingcap/errors"
@@ -83,6 +85,44 @@ func CalcCachingSha2Password(scramble []byte, password string) []byte {
 	return message1
 }
 
+// Taken from https://github.com/go-sql-driver/mysql/pull/1518
+func CalcEd25519Password(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)
+
+	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)
+
+	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)
+
+	return append(R.Bytes(), S.Bytes()...), nil
+}
+
 func EncryptPassword(password string, seed []byte, pub *rsa.PublicKey) ([]byte, error) {
 	plain := make([]byte, len(password)+1)
 	copy(plain, password)