From: Josh Boyer <jwboyer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: Dave Young <hidave.darkstar-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Matthew Garrett
<matthew.garrett-05XSO3Yj/JvQT0dZR+AlfA@public.gmane.org>,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-security-module-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
lxiang-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
Vivek Goyal <vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Subject: Re: [PATCH 10/15] acpi: Ignore acpi_rsdp kernel parameter in a secure boot environment
Date: Wed, 20 Feb 2013 08:39:24 -0500 [thread overview]
Message-ID: <20130220133924.GF362@hansolo.jdub.homelinux.org> (raw)
In-Reply-To: <CABqxG0cJGp7UEREvMW49QA0BfDXPsyEbAuMMLZwcHPdUAKT+Dw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
On Sun, Feb 17, 2013 at 05:00:23PM +0800, Dave Young wrote:
> On Tue, Jan 29, 2013 at 12:42 AM, Matthew Garrett
> <matthew.garrett-05XSO3Yj/JvQT0dZR+AlfA@public.gmane.org> wrote:
> > From: Josh Boyer <jwboyer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> >
> > This option allows userspace to pass the RSDP address to the kernel. This
> > could potentially be used to circumvent the secure boot trust model.
> > We ignore the setting if we don't have the CAP_COMPROMISE_KERNEL capability.
> >
> > Signed-off-by: Josh Boyer <jwboyer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> > ---
> > drivers/acpi/osl.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
> > index bd22f86..88251d2 100644
> > --- a/drivers/acpi/osl.c
> > +++ b/drivers/acpi/osl.c
> > @@ -246,7 +246,7 @@ early_param("acpi_rsdp", setup_acpi_rsdp);
> > acpi_physical_address __init acpi_os_get_root_pointer(void)
> > {
> > #ifdef CONFIG_KEXEC
> > - if (acpi_rsdp)
> > + if (acpi_rsdp && capable(CAP_COMPROMISE_KERNEL))
>
>
> This caused an issue in a kdump test even without secure boot enabled.
> Looks like security subsystem init is not initialized yet at this
> point.
>
> See redhat bug 906225:
> https://bugzilla.redhat.com/show_bug.cgi?id=906225
I've fixed this in a newer revision of the patch. Basically we can't
rely on capable() working at this point because security_init hasn't
been called yet. Sigh.
Despite the desire to not sprinkle if (!secure_boot) checks all over,
I'm thinking less and less that using a CAP is going to work. Maybe
I'll come up with some kind of secure_kernel() function that can be set
per-arch or something and use that instead. At least that would have
the semantics we're looking for without breaking in various places or
causing unintended side-effects in userspace.
josh
next prev parent reply other threads:[~2013-02-20 13:39 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-28 16:42 [PATCH 00/15] Secure boot policy support Matthew Garrett
2013-01-28 16:42 ` [PATCH 01/15] Secure boot: Add new capability Matthew Garrett
2013-01-28 16:42 ` [PATCH 02/15] SELinux: define mapping for new Secure Boot capability Matthew Garrett
2013-01-28 16:42 ` [PATCH 05/15] PCI: Lock down BAR access in secure boot environments Matthew Garrett
[not found] ` <1359391359-25783-1-git-send-email-matthew.garrett-05XSO3Yj/JvQT0dZR+AlfA@public.gmane.org>
2013-01-28 16:42 ` [PATCH 03/15] Secure boot: Add a dummy kernel parameter that will switch on Secure Boot mode Matthew Garrett
2013-01-28 16:42 ` [PATCH 04/15] efi: Enable secure boot lockdown automatically when enabled in firmware Matthew Garrett
2013-01-28 16:42 ` [PATCH 06/15] x86: Lock down IO port access in secure boot environments Matthew Garrett
2013-01-28 16:42 ` [PATCH 14/15] MODSIGN: Import certificates from UEFI Secure Boot Matthew Garrett
2013-01-28 16:42 ` [PATCH 15/15] MODSIGN: Always enforce module signing in a Secure Boot environment Matthew Garrett
2013-02-17 19:19 ` [PATCH 00/15] Secure boot policy support Yves-Alexis Perez
2013-01-28 16:42 ` [PATCH 07/15] ACPI: Limit access to custom_method Matthew Garrett
2013-01-28 16:42 ` [PATCH 08/15] asus-wmi: Restrict debugfs interface Matthew Garrett
2013-01-28 16:42 ` [PATCH 09/15] Restrict /dev/mem and /dev/kmem in secure boot setups Matthew Garrett
2013-01-28 16:42 ` [PATCH 10/15] acpi: Ignore acpi_rsdp kernel parameter in a secure boot environment Matthew Garrett
2013-02-17 9:00 ` Dave Young
[not found] ` <CABqxG0cJGp7UEREvMW49QA0BfDXPsyEbAuMMLZwcHPdUAKT+Dw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-02-20 13:39 ` Josh Boyer [this message]
2013-01-28 16:42 ` [PATCH 11/15] Add EFI signature data types Matthew Garrett
2013-01-28 16:42 ` [PATCH 12/15] Add an EFI signature blob parser and key loader Matthew Garrett
2013-01-28 16:42 ` [PATCH 13/15] MODSIGN: Add module certificate blacklist keyring Matthew Garrett
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