datalen
parameter will overflow a data buffer. NTF's ntpd
driver implementations always set this value to 0 and are therefore not vulnerable to this weakness. If you are running a custom refclock driver in ntpd
and that driver supplies a negative value for datalen
(no custom driver of even minimal competence would do this) then ntpd
would overflow a data buffer. It is even hypothetically possible in this case that instead of simply crashing ntpd
the attacker could effect a code injection attack.
datalen
value is either zero or positive.
ntpd
instances.