linux-kernel - Re: [PATCH v2 0/3] initramfs: add support for xattrs in the initial ram disk

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Date:   Sun, 12 May 2019 17:31:05 +0200
From:   Dominik Brodowski <linux@...inikbrodowski.net>
To:     hpa@...or.com, Mimi Zohar <zohar@...ux.ibm.com>
Cc:     Roberto Sassu <roberto.sassu@...wei.com>, viro@...iv.linux.org.uk,
        linux-security-module@...r.kernel.org,
        linux-integrity@...r.kernel.org, initramfs@...r.kernel.org,
        linux-api@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org, zohar@...ux.vnet.ibm.com,
        silviu.vlasceanu@...wei.com, dmitry.kasatkin@...wei.com,
        takondra@...co.com, kamensky@...co.com, arnd@...db.de,
        rob@...dley.net, james.w.mcmechan@...il.com
Subject: Re: [PATCH v2 0/3] initramfs: add support for xattrs in the initial
 ram disk

On Sun, May 12, 2019 at 03:18:16AM -0700, hpa@...or.com wrote:
> > Couldn't this parsing of the .xattr-list file and the setting of the xattrs
> > be done equivalently by the initramfs' /init? Why is kernel involvement
> > actually required here?
> 
> There are a lot of things that could/should be done that way...

Indeed... so why not try to avoid adding more such "things", and keeping
them in userspace (or in a fork_usermode_blob)?


On Sun, May 12, 2019 at 08:52:47AM -0400, Mimi Zohar wrote:
> It's too late.  The /init itself should be signed and verified.

Could you elaborate a bit more about the threat model, and why deferring
this to the initramfs is too late?

Thanks,
	Dominik