linux-kernel - RE: Re: [PATCH v2 3/3] efi: Capsule update with user helper interface

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Message-ID: <CALCETrWKwQVe46gASNbb0miwcuHe+wirVSO-pQt6uF-Jd6e-bw@mail.gmail.com>
Date:	Thu, 5 Mar 2015 15:08:42 -0800
From:	Andy Lutomirski <luto@...capital.net>
To:	Kweh Hock Leong <hock.leong.kweh@...el.com>
Cc:	Borislav Petkov <bp@...en8.de>,
	Matt Fleming <matt@...sole-pimps.org>,
	"Ong, Boon Leong" <boon.leong.ong@...el.com>,
	"linux-efi@...r.kernel.org" <linux-efi@...r.kernel.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Sam Protsenko <semen.protsenko@...aro.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Ming Lei <ming.lei@...onical.com>
Subject: RE: Re: [PATCH v2 3/3] efi: Capsule update with user helper interface

On Mar 5, 2015 1:19 AM, "Kweh, Hock Leong" <hock.leong.kweh@...el.com> wrote:
>
> > -----Original Message-----
> > From: Andy Lutomirski [mailto:luto@...capital.net]
> > Sent: Wednesday, March 04, 2015 4:38 AM
> >
> > On Mon, Mar 2, 2015 at 9:56 PM, Kweh, Hock Leong
> > <hock.leong.kweh@...el.com> wrote:
> > >
> > > Just to call out that using firmware class auto locate binary feature is limited
> > > to locations:
> > > - "/lib/firmware/updates/" UTS_RELEASE,
> > > - "/lib/firmware/updates",
> > > - "/lib/firmware/" UTS_RELEASE,
> > > - "/lib/firmware"
> > > and one custom path which inputted during firmware_class module load
> > > time or kernel boot up time.
> > >
> > > It is just not like the user helper interface which allow load the binary at
> > > any path/location.
> > >
> > > This really is not a big deal. User should cope with it.
> >
> > No, it's a big deal, and the user should not cope.
> >
> > The user *should not* be required to have write access to anything in
> > /lib to install a UEFI capsule that they download from their
> > motherboard vendor's website.  /lib belongs to the distro, and UEFI
> > capsules do not belong to the distro.  In this regard, UEFI capsules
> > are completely unlike your wireless card firmware, your cpu microcode,
> > etc.
> >
> > Imagine systems using NFS root, Atomic-style systems (e.g. ostree),
> > systems that boot off squashfs, etc.  They should still be able to
> > load capsules.  The basic user interface that should work is:
> >
> > # uefi-load-capsule /path/to/capsule
> >
> > or:
> >
> > # uefi-load-capsule - </path/to/capsule
> >
> > I don't really care how uefi-load-capsule is implemented, as long as
> > it's straightforward, because people will screw it up if it isn't
> > straightforward.
> >
> > Why is it so hard to have a file in sysfs that you write the capsule
> > to using *cat* (not echo) and that will return an error code if cat
> > fails?  Is it because you don't know where the end of the capsule is?
> > if so, ioctl is designed for exactly this purpose.
> >
> > TBH, I find this thread kind of ridiculous.  The problem that you're
> > trying to solve is extremely simple, the functionality that userspace
> > needs is trivial, and all of these complex proposals for how it should
> > work are an artifact of the fact that the kernel-internal interfaces
> > you're using for it are not well suited to the problem at hand.
> >
> > --Andy
>
> Sorry, I may not catch your point correctly. Are you trying to tell that
> a "normal" user can perform efi capsule update. But a "normal" user
> does not have the right to install or copy the capsule binary into
> "/lib/firmware/". So, there is a need to make this capsule module to
> allow uploading the capsule binary at any path or location other than
> "/lib/firmware/".
>
> Is this what you mean?

No.  Only root should be able to load capsules, but even root may not
be able to write to /lib.

--Andy

>
>
> Regards,
> Wilson
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