1. Why is it a mandatory requirement?
2. How can it possibly be uniformly implemented.
E.g.: curl <some source> | perl -e <some filter> > file
How the hell is _any_ OS going to track origin of 'file'?
What _is_ origin of 'file'?
Add an arbitrary number of netcat-over-UDP transfers between start and end of process.
Ownership/origin metadata is impossible to track unless it's overlayed on every single bit of of information transiting every process and every network node.
djb simply does a massive hand-wave over this, as far as I can tell. I respect the man a lot, but this totally loses me.
But with a web of trust, you could also identify multiple remote sources as belonging to the same entity.
The example you give would be a bit more complicated, but you would just rewrite curl to attach metadata to file descriptors. Then the OS can have some restrictions about certain programs reading from file descriptors with metadata it deems untrustworthy.
mdls -name kMDItemWhereFroms slides-djb-20140710-a4.pdf
kMDItemWhereFroms = (
"http://cr.yp.to/talks/2014.07.10/slides-djb-20140710-a4.pdf",
""
)I'd love to set filters on file actions like, "after an image/pdf/etc has been downloaded prevent any program from loading it until it has been scrubbed through a whitelisting format normalizer running in a VM" if problems are found, alert and blacklist source.
Free technical PDFs make a great vehicle into a research org.
Without this, it because difficult to ensure security policies are subverted by users. There are also some really powerful security benefits when essentially nothing is anonymous.