Use strn functions and improve error handling. Even if we know the strings are NULL terminated we use length terminated string functions after a first strlen this makes it easier to assert that at one point we know the string is terminated and afterwards use the length of that.

<!DOCTYPE RCC><RCC version="1.0">
<qresource prefix="/certs">
    <file alias="kolab.org">certificates/kolab.org.der</file>
</qresource>
</RCC>