packets: add regression test for #801 (#802)

Updates #801

packets_test.go

@@ -9,6 +9,7 @@
 package mysql
 
 import (
+	"bytes"
 	"errors"
 	"net"
 	"testing"
@@ -280,3 +281,37 @@ func TestReadPacketFail(t *testing.T) {
 		t.Errorf("expected ErrInvalidConn, got %v", err)
 	}
 }
+
+// https://github.com/go-sql-driver/mysql/pull/801
+// not-NUL terminated plugin_name in init packet
+func TestRegression801(t *testing.T) {
+	conn := new(mockConn)
+	mc := &mysqlConn{
+		buf:      newBuffer(conn),
+		cfg:      new(Config),
+		sequence: 42,
+		closech:  make(chan struct{}),
+	}
+
+	conn.data = []byte{72, 0, 0, 42, 10, 53, 46, 53, 46, 56, 0, 165, 0, 0, 0,
+		60, 70, 63, 58, 68, 104, 34, 97, 0, 223, 247, 33, 2, 0, 15, 128, 21, 0,
+		0, 0, 0, 0, 0, 0, 0, 0, 0, 98, 120, 114, 47, 85, 75, 109, 99, 51, 77,
+		50, 64, 0, 109, 121, 115, 113, 108, 95, 110, 97, 116, 105, 118, 101, 95,
+		112, 97, 115, 115, 119, 111, 114, 100}
+	conn.maxReads = 1
+
+	authData, pluginName, err := mc.readInitPacket()
+	if err != nil {
+		t.Fatalf("got error: %v", err)
+	}
+
+	if pluginName != "mysql_native_password" {
+		t.Errorf("expected plugin name 'mysql_native_password', got '%s'", pluginName)
+	}
+
+	expectedAuthData := []byte{60, 70, 63, 58, 68, 104, 34, 97, 98, 120, 114,
+		47, 85, 75, 109, 99, 51, 77, 50, 64}
+	if !bytes.Equal(authData, expectedAuthData) {
+		t.Errorf("expected authData '%v', got '%v'", expectedAuthData, authData)
+	}
+}