From: Jean Delvare <jdelvare@suse.de>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>, Thomas <trenn@suse.de>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: /dev/mem and secure boot
Date: Fri, 6 Sep 2019 17:07:37 +0200 [thread overview]
Message-ID: <20190906170737.1a00178c@endymion> (raw)
In-Reply-To: <20190906121510.GA17328@kroah.com>
On Fri, 6 Sep 2019 14:15:10 +0200, Greg Kroah-Hartman wrote:
> On Fri, Sep 06, 2019 at 01:02:21PM +0200, Jean Delvare wrote:
> > I've been bitten recently by mcelog not working on machines started in
> > secure boot mode. mcelog tries to read DMI information from /dev/mem
> > and fails to open it.
>
> What do you mean by "secure boot"? Is this matthew's patchset that
> restricts /dev/mem/ or something else?
I mean that early in the kernel log is:
Secure boot enabled and kernel locked down
> > This made me wonder: if not even root can read /dev/mem (nor, I
> > suppose, /dev/kmem and /dev/port) in secure boot mode, why are we
> > creating these device nodes at all in the first place? Can't we detect
> > that we are in secure boot mode and skip that step, and reap the rewards
> > (faster boot, lower memory footprint and less confusion)?
>
> Sure, feel free to not register it at all if the mode is enabled.
>
> thanks,
>
> greg k-h
--
Jean Delvare
SUSE L3 Support
next prev parent reply other threads:[~2019-09-06 15:07 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-06 11:02 /dev/mem and secure boot Jean Delvare
2019-09-06 12:15 ` Greg Kroah-Hartman
2019-09-06 15:07 ` Jean Delvare [this message]
2019-09-06 15:08 ` Jean Delvare
2019-09-09 13:09 ` Jean Delvare
2019-09-12 10:44 ` Thomas Renninger
2019-09-16 9:38 ` David Howells
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