Re: [PATCH] kexec: Do not verify the signature without the lockdown or mandatory signature

[Jiri Bohac]

On Mon, May 25, 2020 at 01:23:51PM +0800, Lianbo Jiang wrote:
> So, here, let's simplify the logic to improve code readability. If the
> KEXEC_SIG_FORCE enabled or kexec lockdown enabled, signature verification
> is mandated. Otherwise, we lift the bar for any kernel image.

I agree completely; in fact that was my intention when
introducing the code, but I got overruled about the return codes:
https://lore.kernel.org/lkml/20180119125425.l72meyyc2qtrriwe@xxxxxxxxxxxxx/

I like this simplification very much, except this part:

> +	if (ret) {
> +		pr_debug("kernel signature verification failed (%d).\n", ret);

...

> -		pr_notice("kernel signature verification failed (%d).\n", ret);

I think the log level should stay at most PR_NOTICE when the
verification failure results in rejecting the kernel. Perhaps
even lower.

In case verification is not enforced and the failure is
ignored, KERN_DEBUG seems reasonable.

Regards,

-- 
Jiri Bohac <jbohac@xxxxxxx>
SUSE Labs, Prague, Czechia