From: Dave Young <dyoung@redhat.com>
Date: Wed, 8 Nov 2017 15:11:32 +0000
Subject: [07/29] Copy secure_boot flag in boot params across kexec reboot
Origin: https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/commit?id=a6b7f780bdaa731f3e2970d65dcd52fe9ba2409d

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>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: "Lee, Chun-Yi" <jlee@suse.com>
cc: kexec@lists.infradead.org
---
 arch/x86/kernel/kexec-bzimage64.c | 1 +
 1 file changed, 1 insertion(+)

Index: linux/arch/x86/kernel/kexec-bzimage64.c
===================================================================
--- linux.orig/arch/x86/kernel/kexec-bzimage64.c
+++ linux/arch/x86/kernel/kexec-bzimage64.c
@@ -182,6 +182,7 @@ setup_efi_state(struct boot_params *para
 	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;
