[RFC PATCH 1/2] security, capabilities: create CAP_TRUSTED

[nicolas at belouin.fr]

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From: Nicolas Belouin <nicolas at belouin.fr>
Message-ID: <99179B10-4EAE-4FAB-9D14-B885156261B3 at belouin.fr>



On October 21, 2017 6:03:02 PM GMT+02:00, "Serge E. Hallyn" <serge at hallyn.com> wrote:
>Quoting Nicolas Belouin (nicolas at belouin.fr):
>> with CAP_SYS_ADMIN being bloated, the usefulness of using it to
>> flag a process to be entrusted for e.g reading and writing trusted
>> xattr is near zero.
>> CAP_TRUSTED aims to provide userland with a way to mark a process as
>> entrusted to do specific (not specially admin-centered) actions. It
>> would for example allow a process to red/write the trusted xattrs.
>
>You say "for example".  Are you intending to add more uses?  If so,
>what
>are they?  If not, how about renaming it CAP_TRUSTED_XATTR?
>

I don't see any other use for now, but I don't want it to be too narrow and non usable in a similar context in the future. So I believe the underlying purpose of marking a process as "trusted" (even if for now it only means rw permission on trusted xattr) is more meaningful.

>What all does allowing writes to trusted xattrs give you?  There are
>the overlayfs whiteouts, what else?

Nicolas
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