A cloneable class that performs this check in its constructor needs to perform the same check in its clone()
method.
When a class's clone()
method is invoked, the constructor for the class being cloned is not invoked. Thus, if a SecurityManager or AccessController check is present in the constructor of a cloneable class, the same check must also be present in the clone method of the class. Otherwise, the security check will be bypassed when the class is cloned.
Example 1: The following code contains a SecurityManager
check in the constructor but not in the clone()
method.
public class BadSecurityCheck implements Cloneable {
private int id;
public BadSecurityCheck() {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPermission(new BadPermission("BadSecurityCheck"));
}
id = 1;
}
public Object clone() throws CloneNotSupportedException {
BadSecurityCheck bsm = (BadSecurityCheck)super.clone();
return null;
}
}
[1] "Secure Coding Guidelines for the Java Programming Language, version 2.0" Sun Microsystems, Inc. [Online]. [Accessed: Aug. 30, 2007]. Sun Microsystems, Inc.
[2] Standards Mapping - Common Weakness Enumeration - (CWE) CWE ID 358
[3] C. Lai Java Insecurity: Accounting for Subtleties That Can Compromise Code