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>
Signed-off-by: David Howells <dhowells@redhat.com>
Gbp-Pq: Topic features/all/lockdown
Gbp-Pq: Name 0046-Copy-secure_boot-flag-in-boot-params-across-kexec-re.patch

diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index d0a814a9d96ac5412b1216060169d53a69133aea..3551bcaa1eafd6320e5d0de535bf4accda06bf61 100644 (file)
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -179,6 +179,7 @@ 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;