Synopsis

Ensure that unsigned integer operations do not wrap.

Enabled by default

No

Severity/Certainty

High/High

Full description

Unsigned integer operations can wrap if the resulting value cannot be represented by the underlying representation of the integer. Integer values must not be allowed to wrap. This check warns on other wrapping cases except the ones already covered by CERT-INT30-C_a.

Coding standards

Code examples

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

void example(unsigned int a, unsigned int b) {
    unsigned int usum = a + b;
}

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

#include <limits.h>

void example(unsigned int a, unsigned int b) {
    unsigned int usum;
    if (UINT_MAX - a < b) {
        /* Handle error */
    } else {
        usum = a + b;
    }
}