Suricata dhcp: unbounded transactions in unidirectional traffic can lead to resource exhaustion

Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. From 8.0.0 until 8.0.6, the DHCP parser in rust/src/dhcp/dhcp.rs creates stateless transactions without recording their packet direction with AppLayerTxData::for_direction(), so a sensor that observes only one direction cannot mark the unseen direction inspected or free completed transactions. The RDP parser in rust/src/rdp/rdp.rs has the same direction-state defect. The per-flow transaction list can grow without bound and cleanup repeatedly scans it, causing increasing CPU and memory consumption and eventual denial of service. This issue is fixed in version 8.0.6.