[PATCH v2 04/24] Add security policy support

[Sascha Hauer]

On Mon, Sep 22, 2025 at 06:14:36PM +0200, Ahmad Fatoum wrote:
> On 17.09.25 15:53, Sascha Hauer wrote:
> > +bool is_allowed(const struct security_policy *policy, unsigned option)
> > +{
> > +	policy = policy ?: active_policy;
> > +
> > +	if (WARN(option > SCONFIG_NUM))
> > +		return false;
> > +
> > +	if (!policy && *CONFIG_SECURITY_POLICY_INIT) {
> > +		security_policy_select(CONFIG_SECURITY_POLICY_INIT);
> > +		policy = active_policy;
> > +	}
> > +
> > +	if (policy) {
> > +		bool allow = __is_allowed(policy, option);
> > +
> > +		policy_debug(policy, option, "%s for %pS\n",
> > +			 allow ? "allowed" : "denied", (void *)_RET_IP_);
> > +
> > +		return allow;
> > +	}
> > +
> > +	if (IS_ENABLED(CONFIG_SECURITY_POLICY_DEFAULT_PERMISSIVE))
> > +		pr_warn_once("option %s checked before security policy was set!\n",
> > +			     sconfig_name(option));
> > +	else
> > +		return false;
> 
> Not having a security policy selected outside of permissive mode is a bug, so
> I don't think silent forbidding is a good idea.
> 
> At the very least, we should print the warning outside permissive mode as well,
> if only to tell people if they select the policy too late in their board code.
> 
> What's wrong with a panic though?

The rationale was:

- It's forbidden, so it's safe
- I assumed the caller would print an error
- It might offer a bit more flexibility on when we select the security
  policy

Anyway, we still make this more relaxed in the future should we want to.
For now I have put back the panic() here.

Sascha

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