Re: [PATCH v3] lockdown,selinux: fix wrong subject in some SELinux lockdown checks

[Thomas Gleixner]

On Wed, Jun 16 2021 at 10:51, Ondrej Mosnacek wrote:
> diff --git a/arch/x86/mm/testmmiotrace.c b/arch/x86/mm/testmmiotrace.c
> index bda73cb7a044..c43a13241ae8 100644
> --- a/arch/x86/mm/testmmiotrace.c
> +++ b/arch/x86/mm/testmmiotrace.c
> @@ -116,7 +116,7 @@ static void do_test_bulk_ioremapping(void)
>  static int __init init(void)
>  {
>  	unsigned long size = (read_far) ? (8 << 20) : (16 << 10);
> -	int ret = security_locked_down(LOCKDOWN_MMIOTRACE);
> +	int ret = security_locked_down(current_cred(), LOCKDOWN_MMIOTRACE);

I have no real objection to those patches, but it strikes me odd that
out of the 62 changed places 58 have 'current_cred()' and 4 have NULL as
argument.

I can't see why this would ever end up with anything else than
current_cred() or NULL and NULL being the 'special' case. So why not
having security_locked_down_no_cred() and make current_cred() implicit
for security_locked_down() which avoids most of the churn and just makes
the special cases special. I might be missing something though.

Thanks,

        tglx