Native sql query- SQL Injection Attack - java

I'm working with JPA. How could my application be SQL injection safe if I'm using a native sql query (not entity query)? I need to build the native sql query with the data submitted by a user from a html form.
If I use parameters in the native sql I can avoid SQL injection attacks, but my problem is that I can't be sure how many data fields are being submitted by the user.

You should use positional parameters binding:
String queryString = "select * from EMP e where e.name = ?1";
Query query = em.createNativeQuery(queryString, Employee.class);
query.setParameter(1, "Mickey");
Please note that you should not use named parameters binding (:empName) in your query as JPA Spec says
Only positional parameter binding may be portably used for native queries.
This should secure you from SQL Injection attacks.

Related

fetching single column values in JPA

I want to get all the values from a particular column in JPA and store all values into a list. currently, I am using the below approach but I am getting records in something else format.can someone please help me out
Query q1 = factory.createNativeQuery("select * from booking_attendee where booking_id="+id);
List<String> em1=q1.getResultList();
return em1;
query otput
em=[[Ljava.lang.Object;#68606667, [Ljava.lang.Object;#2cd7f99a, [Ljava.lang.Object;#137a5a5, [Ljava.lang.Object;#a45cc1c, [Ljava.lang.Object;#61fdc06d, [Ljava.lang.Object;#72f5eee1, [Ljava.lang.Object;#4e536797]
If you want to create a native query for this, it is more about how to solve this in SQL. You do not say SELECT * which means all columns. You would have to say SELECT your_column_name to select only a specific column.
Query q1 = factory.createNativeQuery("SELECT your_column FROM booking_attendee");
List<String> em1 = q1.getResultList();
The WHERE clause could and should be defined with the parameter binding of JPA. There are several advantages concerning performance and SQL injection.
Named parameter binding is special to the persistence provider (e.g. Hibernate). The common way for JPA is using ? to let your code be portable to other providers.
Query q1 = factory.createNativeQuery("SELECT your_column FROM booking_attendee b WHERE b.booking_id = ?");
q1.setParameter(1, id);
List<String> em1 = q1.getResultList();
Native queries offer the possibilities to use original SQL. Like this, some features which are specific for your database could be used with this. Nevertheless, if you do not have very specific SQL code, you should also have a look in JPQL, the specific query language of JPA, and the JPA Criteria API which offers advantages when you want to refactor your code, shows errors during compile time and makes the dynamic creation of queries easier.

How to prevent sql injection in JPA

I am using below jpa code. How can we prevent below code from sql injections?
List<Document> docs= em.createQuery("SELECT c FROM Document c WHERE c.docId = :docId ", Document.class)
.setParameter("docId", docId).getResultList();
http://www.adam-bien.com/roller/abien/entry/preventing_injection_in_jpa_query
It already is protected against SQL injection. Your code is using parameters.
Also if you want, you can use Criteria APIs to build the same query.

Execute dynamic query with Spring Data JPA

#Query(value = "SELECT * FROM H4 WHERE 1")
List getResult();
Instead of the query "SELECT * FROM H4 WHERE 1" I want to put a String variable containing query generated elsewhere.
#Query, like any other annotation, uses a compile time constant to define attributes. You can't define it's value in runtime unless you plan to hack the Spring Data JPA framework.
You should use either Specifications with criteria, Query by example or JPQL to define and execute your dynamic query.
Create constants and set the value as below.
#Query(value = ApplicationConstantClass.QUERY_STRING_CONSTANT)
List getResult();
or Use EntityManager or SessionFactory of hibernate to execute dynamically generated query.

How to perform some operation based on SQL return code I am using spring data JPA

I am working on some project where I used spring data jpa to query against DB2. Suppose used query "Select a,b from sometable where a='XX' ". So now based on sql code I want to perform some operation but how I will get sql return code as I am using spring data JPA.
Thanks in advance

How to create native queries in Spring?

I have a spring application that should connect to an existing database and just query an entity for existence based on some attributes.
I don't want to create a #Entity class for this. But I still want to use the spring managed EntityManager etc.
When using Spring, what is the best approach to just query a select for that entity? Using em.createNamedQuery(QUERY); with String QUERY = "SELECT count(*) from my_table where username =: username AND email := email)";?
Answers from #predrag-maric and #pL4Gu33 are both correct but if you use JPA in your project (for example, Hibernate) you might consider using #NamedNativeQuery annotation as well.
More about named native queries.
simple example of native query
#PersistenceContext
EntityManager em;
public String test(Integer id)
{
Query query = em.createNativeQuery("SELECT name FROM Accounts where id=?");
query.setParameter(1,id);
return query.getSingleResult();
}
You can use this method from entitymanager. http://docs.oracle.com/javaee/6/api/javax/persistence/EntityManager.html#createNativeQuery%28java.lang.String%29
Use em.createNativeQuery(QUERY). Also, you'll have to use positional parameters (?1) instead of named parameters (:email), because only positional parameters are supported by JPA in native queries.

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