Re: [PATCH] apparmor: Fix use-after-free in aa_audit_rule_init

[Markus Elfring]

> â But after this release the the return statement
> tries to access the label field of the rule which results in
> use-after-free. Before releaseing the rule, copy errNo and return it
> after releasing rule.

Please avoid a duplicate word and a typo in this change description.


â
> +++ b/security/apparmor/audit.c
â
> @@ -197,8 +198,9 @@ int aa_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
>  	rule->label = aa_label_parse(&root_ns->unconfined->label, rulestr,
>  				     GFP_KERNEL, true, false);
>  	if (IS_ERR(rule->label)) {
> +		err = rule->label;

How do you think about to define the added local variable in this if branch directly?

+		int err = rule->label;

>  		aa_audit_rule_free(rule);
> -		return PTR_ERR(rule->label);
> +		return PTR_ERR(err);
>  	}
>
>  	*vrule = rule;


Regards,
Markus