File path validation during file transfer - too strict?

[jenstopp]

Currently, any file to be transmitted must be named on the dutctl cmdline.

[sylv-io]

IMHO, this behavior makes sense from a security standpoint. It is not advisable to allow the dutagent to access arbitrary files without client-side verification. Verifying that the file appears in the dutctl command line ensures that the client user consents to providing access to the file.

[RiSKeD]

#249 had to remove this check because the dutagent configures a fixed destination path to copy to on the client. In my opinion this needs further remedy. Maybe prompt the user to accept the file? It will be removed for now though.