Synopsis

Do not read uninitialized memory.

Enabled by default

Yes

Severity/Certainty

High/Medium

Full description

Uninitialized automatic variables or dynamically allocated memory has indeterminate values, which for objects of some types, can be a trap representation. Reading such trap representations is undefined behavior; it can cause a program to behave in an unexpected manner and provide an avenue for attack. This check is identical to MISRAC2012-Rule-9.1_a, PTR-uninit-pos.

Coding standards

Code examples

The following code example fails the check and will give a warning:

void example(void) {
  int *p;
  *p = 4;  //p is uninitialized
}

The following code example passes the check and will not give a warning about this issue:

void example(void) {
  int *p,a;
  p = &a;
  *p = 4;  //OK - p holds a valid address
}