CS.NRE.FUNC.CALL.MUST
An object reference value from a call to a function that might return null will be passed to a function that might dereference it without checking for null.
Vulnerability and risk
Dereferencing a null object reference is a critical runtime problem that will crash the application on some operating systems and throw a runtime exception on others.
Example 1
1 public class A {
2 public void abc() {}
3 public void foo(A a) {
4 if (flag2)
5 return;
6 a.abc();
7 }
8
9 public A boo() {
10 if (flag3)
11 return new A();
12 return null;
13 }
14
15 public void var() {
16 A a = boo();
17 foo(a);
18 }
19
20 private bool flag2;
21 private bool flag3;
22 }
Klocwork produces an issue report (CS.NRE.FUNC.CALL.MUST) at line 17 for variable 'a'. Variable 'a' is assigned to a value which might be null, and which comes from a call to function 'boo' at line 16. This variable will be passed as argument 1 to function 'foo' at line 17, which may dereference it.
External guidance
Security training
Application security training materials provided by Secure Code Warrior.
