FreeBSD: VID-3110b29e-c82d-4287-9f6c-db82bb883b1e: zeek -- potential DoS vulnerabilities

Tim Wojtulewicz of Corelight reports: Fix a possible overflow and crash in the ARP analyzer when receiving a specially crafted packet. Due to the possibility of this happening with packets received from the network, this is a potential DoS vulnerability. Fix a possible overflow and crash in the Modbus analyzer when receiving a specially crafted packet. Due to the possibility of this happening with packets received from the network, this is a potential DoS vulnerability. Fix two possible crashes when converting IP headers for output via the raw_packet event. Due to the possibility of this happening with packets received from the network, this is a potential DoS vulnerability. Note that the raw_packet event is not enabled by default so these are likely low-severity issues. Fix an abort related to an error related to the ordering of record fields when processing DNS EDNS headers via events. Due to the possibility of this happening with packets received from the network, this is a potential DoS vulnerability. Note that the dns_EDNS events are not implemented by default so this is likely a low-severity issue.