CVE-2019-16411

An issue was discovered in Suricata 4.1.4. By sending multiple IPv4 packets
that have invalid IPv4Options, the function IPV4OptValidateTimestamp in
decode-ipv4.c tries to access a memory region that is not allocated. There
is a check for o->len < 5 (corresponding to 2 bytes of header and 3 bytes
of data). Then, “flag = *(o->data + 3)” places one beyond the 3 bytes,
because the code should have been “flag = *(o->data + 1)” instead.