Kexec Archive on lore.kernel.org
 help / color / mirror / Atom feed
From: Kees Cook <keescook@chromium.org>
To: Matthew Garrett <matthewgarrett@google.com>
Cc: linux-api@vger.kernel.org, kexec@lists.infradead.org,
	jmorris@namei.org, Matthew Garrett <mjg59@google.com>,
	linux-kernel@vger.kernel.org, David Howells <dhowells@redhat.com>,
	linux-security-module@vger.kernel.org,
	Dave Young <dyoung@redhat.com>
Subject: Re: [PATCH V34 07/29] Copy secure_boot flag in boot params across kexec reboot
Date: Sat, 22 Jun 2019 16:53:19 -0700	[thread overview]
Message-ID: <201906221653.DDCB3C898@keescook> (raw)
In-Reply-To: <20190622000358.19895-8-matthewgarrett@google.com>

On Fri, Jun 21, 2019 at 05:03:36PM -0700, Matthew Garrett wrote:
> From: Dave Young <dyoung@redhat.com>
> 
> Kexec reboot in case secure boot being enabled does not keep the secure
> boot mode in new kernel, so later one can load unsigned kernel via legacy
> kexec_load.  In this state, the system is missing the protections provided
> by secure boot.
> 
> Adding a patch to fix this by retain the secure_boot flag in original
> kernel.
> 
> secure_boot flag in boot_params is set in EFI stub, but kexec bypasses the
> stub.  Fixing this issue by copying secure_boot flag across kexec reboot.
> 
> Signed-off-by: Dave Young <dyoung@redhat.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

-Kees

> Signed-off-by: David Howells <dhowells@redhat.com>
> Signed-off-by: Matthew Garrett <mjg59@google.com>
> cc: kexec@lists.infradead.org
> ---
>  arch/x86/kernel/kexec-bzimage64.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
> index 22f60dd26460..4243359ac509 100644
> --- a/arch/x86/kernel/kexec-bzimage64.c
> +++ b/arch/x86/kernel/kexec-bzimage64.c
> @@ -182,6 +182,7 @@ setup_efi_state(struct boot_params *params, unsigned long params_load_addr,
>  	if (efi_enabled(EFI_OLD_MEMMAP))
>  		return 0;
>  
> +	params->secure_boot = boot_params.secure_boot;
>  	ei->efi_loader_signature = current_ei->efi_loader_signature;
>  	ei->efi_systab = current_ei->efi_systab;
>  	ei->efi_systab_hi = current_ei->efi_systab_hi;
> -- 
> 2.22.0.410.gd8fdbe21b5-goog
> 

-- 
Kees Cook

_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

  reply	other threads:[~2019-06-22 23:53 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20190622000358.19895-1-matthewgarrett@google.com>
2019-06-22  0:03 ` [PATCH V34 06/29] kexec_load: Disable at runtime if the kernel is locked down Matthew Garrett
2019-06-22 23:52   ` Kees Cook
2019-06-22  0:03 ` [PATCH V34 07/29] Copy secure_boot flag in boot params across kexec reboot Matthew Garrett
2019-06-22 23:53   ` Kees Cook [this message]
2019-06-22  0:03 ` [PATCH V34 08/29] kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE Matthew Garrett
2019-06-24  2:01   ` Dave Young
2019-06-25  2:35     ` Dave Young
2019-06-22  0:03 ` [PATCH V34 09/29] kexec_file: Restrict at runtime if the kernel is locked down Matthew Garrett
2019-06-22 23:54   ` Kees Cook
2019-06-27  4:59   ` James Morris
2019-06-27 15:28     ` Matthew Garrett
2019-06-27 18:14       ` James Morris
2019-06-27 23:17         ` Matthew Garrett

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=201906221653.DDCB3C898@keescook \
    --to=keescook@chromium.org \
    --cc=dhowells@redhat.com \
    --cc=dyoung@redhat.com \
    --cc=jmorris@namei.org \
    --cc=kexec@lists.infradead.org \
    --cc=linux-api@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-security-module@vger.kernel.org \
    --cc=matthewgarrett@google.com \
    --cc=mjg59@google.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox