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Date: Tue, 1 Apr 2014 21:22:35 +0100
From: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Jim Lieb <jlieb@panasas.com>, Jeff Layton <jlayton@redhat.com>,
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        Kees Cook <keescook@chromium.org>
Subject: Re: Thoughts on credential switching
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> Do we include credfd fds sitting in Unix sockets?

Ouch

> Hmm.  What if we had initial_creds and creds, and initial_creds never
> changed unless explicitly requested.  There wouldn't be any way to
> revert to initial_creds, but may_ptrace would check initial_creds
> *and* creds.  This is a little hacky, and it might break Android (I'm
> not really sure how the zygote thing works), but it could do the
> trick.

That mirros setfsuid and seteuid type behaviour so seems sensible enough.