From e3cc5ea4d403078a370e299629da56cd011b6583 Mon Sep 17 00:00:00 2001
From: Herpiko Dwi Aguno <herpiko@gmail.com>
Date: Fri, 21 Jun 2019 21:29:12 +0700
Subject: [PATCH] Fix #2517 : Check for incomplete parentheses to prevent SQL
 injection.

---
 query_test.go | 17 +++++++++++++++++
 scope.go      | 21 +++++++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/query_test.go b/query_test.go
index 15bf8b3c..2b7e0dff 100644
--- a/query_test.go
+++ b/query_test.go
@@ -133,6 +133,23 @@ func TestStringPrimaryKeyForNumericValueStartingWithZero(t *testing.T) {
 		t.Errorf("Fetch a record from with a string primary key for a numeric value starting with zero should work, but failed, zip code is %v", address.ZipCode)
 	}
 }
+func TestStringAgainstIncompleteParentheses(t *testing.T) {
+	type AddressByZipCode struct {
+		ZipCode string `gorm:"primary_key"`
+		Address string
+	}
+
+	DB.AutoMigrate(&AddressByZipCode{})
+	DB.Create(&AddressByZipCode{ZipCode: "00502", Address: "Holtsville"})
+
+	var address AddressByZipCode
+	var addresses []AddressByZipCode
+	_ = DB.First(&address, "address_by_zip_codes=00502)) UNION ALL SELECT NULL,version(),current_database(),NULL,NULL,NULL,NULL,NULL--").Find(&addresses).GetErrors()
+	if len(addresses) > 0 {
+		t.Errorf("Fetch a record from with a string that has incomplete parentheses should be fail, zip code is %v", address.ZipCode)
+	}
+
+}
 
 func TestFindAsSliceOfPointers(t *testing.T) {
 	DB.Save(&User{Name: "user"})
diff --git a/scope.go b/scope.go
index c962c165..541fe522 100644
--- a/scope.go
+++ b/scope.go
@@ -277,6 +277,23 @@ func (scope *Scope) AddToVars(value interface{}) string {
 	return scope.Dialect().BindVar(len(scope.SQLVars))
 }
 
+// IsCompleteParentheses check if the string has complete parentheses to prevent SQL injection
+func (scope *Scope) IsCompleteParentheses(value string) bool {
+	count := 0
+	for i, _ := range value {
+		if value[i] == 40 { // (
+			count++
+		} else if value[i] == 41 { // )
+			count--
+		}
+		if count < 0 {
+			break
+		}
+		i++
+	}
+	return count == 0
+}
+
 // SelectAttrs return selected attributes
 func (scope *Scope) SelectAttrs() []string {
 	if scope.selectAttrs == nil {
@@ -556,6 +573,10 @@ func (scope *Scope) buildCondition(clause map[string]interface{}, include bool)
 		}
 
 		if value != "" {
+			if !scope.IsCompleteParentheses(value) {
+				scope.Err(fmt.Errorf("incomplete parentheses found: %v", value))
+				return
+			}
 			if !include {
 				if comparisonRegexp.MatchString(value) {
 					str = fmt.Sprintf("NOT (%v)", value)