fprime: F´: Arbitrary File Write in Svc::FileUplink via attacker-controlled StartPacket.destinationPath

F´ (F Prime) is a framework that enables development and deployment of spaceflight and other embedded software applications. Prior to 4.3.0, Svc::FileUplink handling of Fw::FilePacket::StartPacket destination paths FileUplink copies the packet-controlled destinationPath and opens it for writing without canonicalization or confinement to an upload directory. When a peer able to send file-uplink packets supplies an absolute, traversing, or otherwise attacker-selected writable destination path, files can be created or overwritten at attacker-selected writable filesystem locations, affecting integrity and potentially availability. This issue is fixed in version 4.3.0.