Re: [RFC] /dev/ioasid uAPI proposal

Enrico Weigelt, metux IT consult
2021-06-09T08:52:24Z

On 08.06.21 21:00, Jason Gunthorpe wrote:

> Eg I can do open() on a file and I get to keep that FD. I get to keep
> that FD even if someone later does chmod() on that file so I can't
> open it again.
>
> There are lots of examples where a one time access control check
> provides continuing access to a resource. I feel the ongoing proof is
> the rarity in Unix.. 'revoke' is an uncommon concept in Unix..

Yes, it's even possible that somebody w/ privileges opens an fd and
hands it over to somebody unprivileged (eg. via unix socket). This is
a very basic unix concept. If some (already opened) fd now suddenly
behaves differently based on the current caller, that would be a break
with traditional unix semantics.

--mtx

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Enrico Weigelt, metux IT consult
Free software and Linux embedded engineering
info@metux.net -- +49-151-27565287