Re: [PATCH] new syscall: flink

[Werner Almesberger <wa@almesberger.net>]

I wrote:
> Example: I write some kind of RAID mounted at /world, that contains
> my disk under /world/disk, and some Flash storage under /world/flash.
> I protect /world/flash against writes by other people. If a
> read-only FD could be turned into something writeable, some malicious
> creature could "wear out" my Flash by writing to it a lot of times.

Just to clarify: the file in question would be inaccessible for the
abuser, and the read-only fd would have to be handed out by some
access mediator.

Obviously, if the abuser obtains a read-only fd directly by opening
a file, the hypothetical flink couldn't be used for privilege
escalation.

- Werner

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 / Werner Almesberger, Buenos Aires, Argentina         wa@almesberger.net /
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