efi_loader: GetNextMonotonicCount() check parameter

Do not write to address indicated by NULL pointer.

UEFI SCT II 2.6 (2017), 3.6.5 GetNextMonotonicCount(), 5.1.5.5.1

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index ce6ca06..971bd5f 100644 (file)
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -1916,10 +1916,17 @@ static efi_status_t EFIAPI efi_exit_boot_services(efi_handle_t image_handle,
 static efi_status_t EFIAPI efi_get_next_monotonic_count(uint64_t *count)
 {
        static uint64_t mono;
+       efi_status_t ret;
 
        EFI_ENTRY("%p", count);
+       if (!count) {
+               ret = EFI_INVALID_PARAMETER;
+               goto out;
+       }
        *count = mono++;
-       return EFI_EXIT(EFI_SUCCESS);
+       ret = EFI_SUCCESS;
+out:
+       return EFI_EXIT(ret);
 }
 
 /**