Fix bug on insert where (#1436)

* fix bug on insert where

* fix bug

* fix lint

Author: lunny

session_insert_test.go

@@ -908,6 +908,15 @@ func TestInsertWhere(t *testing.T) {
 	assert.True(t, has)
 	assert.EqualValues(t, "trest3", j3.Name)
 	assert.EqualValues(t, 3, j3.Index)
+
+	inserted, err = testEngine.Table(new(InsertWhere)).Where("repo_id=?", 1).
+		SetExpr("`index`", "coalesce(MAX(`index`),0)+1").
+		Insert(map[string]interface{}{
+			"repo_id": 1,
+			"name":    "10';delete * from insert_where; --",
+		})
+	assert.NoError(t, err)
+	assert.EqualValues(t, 1, inserted)
 }
 
 type NightlyRate struct {

statement_args.go

@@ -6,17 +6,60 @@ package xorm
 
 import (
 	"fmt"
+	"reflect"
+	"strings"
+	"time"
 
 	"xorm.io/builder"
 	"xorm.io/core"
 )
 
+func quoteNeeded(a interface{}) bool {
+	switch a.(type) {
+	case int, int8, int16, int32, int64:
+		return false
+	case uint, uint8, uint16, uint32, uint64:
+		return false
+	case float32, float64:
+		return false
+	case bool:
+		return false
+	case string:
+		return true
+	case time.Time, *time.Time:
+		return true
+	case builder.Builder, *builder.Builder:
+		return false
+	}
+
+	t := reflect.TypeOf(a)
+	switch t.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return false
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		return false
+	case reflect.Float32, reflect.Float64:
+		return false
+	case reflect.Bool:
+		return false
+	case reflect.String:
+		return true
+	}
+
+	return true
+}
+
+func convertArg(arg interface{}) string {
+	if quoteNeeded(arg) {
+		argv := fmt.Sprintf("%v", arg)
+		return "'" + strings.Replace(argv, "'", "''", -1) + "'"
+	}
+
+	return fmt.Sprintf("%v", arg)
+}
+
 func (statement *Statement) writeArg(w *builder.BytesWriter, arg interface{}) error {
 	switch argv := arg.(type) {
-	case string:
-		if _, err := w.WriteString("'" + argv + "'"); err != nil {
-			return err
-		}
 	case bool:
 		if statement.Engine.dialect.DBType() == core.MSSQL {
 			if argv {
@@ -50,7 +93,7 @@ func (statement *Statement) writeArg(w *builder.BytesWriter, arg interface{}) er
 			return err
 		}
 	default:
-		if _, err := w.WriteString(fmt.Sprintf("%v", argv)); err != nil {
+		if _, err := w.WriteString(convertArg(arg)); err != nil {
 			return err
 		}
 	}