kexec-uefi-copy-secure_boot-flag-in-boot-params.patch

From: Dave Young <dyoung@redhat.com>

[PATCH] kexec/uefi: copy secure_boot flag in boot params across kexec reboot

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>
---
 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 9642b9b..0539ec7 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -178,6 +178,7 @@ 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;