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Message-ID: <ce1fbc8baf5359b698bf4420e602cc3a5a2a1f44.camel@linux.ibm.com>
Subject: Re: [PATCH v10 16/27] ima: Implement ima_free_policy_rules() for
 freeing of an ima_namespace
From:   Mimi Zohar <zohar@linux.ibm.com>
To:     Stefan Berger <stefanb@linux.ibm.com>,
        linux-integrity@vger.kernel.org
Cc:     serge@hallyn.com, christian.brauner@ubuntu.com,
        containers@lists.linux.dev, dmitry.kasatkin@gmail.com,
        ebiederm@xmission.com, krzysztof.struczynski@huawei.com,
        roberto.sassu@huawei.com, mpeters@redhat.com, lhinds@redhat.com,
        lsturman@redhat.com, puiterwi@redhat.com, jejb@linux.ibm.com,
        jamjoom@us.ibm.com, linux-kernel@vger.kernel.org,
        paul@paul-moore.com, rgb@redhat.com,
        linux-security-module@vger.kernel.org, jmorris@namei.org
Date:   Fri, 18 Feb 2022 12:09:34 -0500
In-Reply-To: <20220201203735.164593-17-stefanb@linux.ibm.com>
References: <20220201203735.164593-1-stefanb@linux.ibm.com>
         <20220201203735.164593-17-stefanb@linux.ibm.com>
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On Tue, 2022-02-01 at 15:37 -0500, Stefan Berger wrote:
> Implement ima_free_policy_rules() that is needed when an ima_namespace
> is freed.
> 
> Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
> 
> ---
> v10:
>   - Not calling ima_delete_rules() anymore
>   - Move access check from ima_delete_rules into very last patch
> 
>  v9:
>   - Only reset temp_ima_appraise when using init_ima_ns.
> ---
>  security/integrity/ima/ima.h        |  1 +
>  security/integrity/ima/ima_policy.c | 14 ++++++++++++++
>  2 files changed, 15 insertions(+)
> 
> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> index aea8fb8d2854..8c757223d549 100644
> --- a/security/integrity/ima/ima.h
> +++ b/security/integrity/ima/ima.h
> @@ -329,6 +329,7 @@ void ima_update_policy_flags(struct ima_namespace *ns);
>  ssize_t ima_parse_add_rule(struct ima_namespace *ns, char *rule);
>  void ima_delete_rules(struct ima_namespace *ns);
>  int ima_check_policy(struct ima_namespace *ns);
> +void ima_free_policy_rules(struct ima_namespace *ns);
>  void *ima_policy_start(struct seq_file *m, loff_t *pos);
>  void *ima_policy_next(struct seq_file *m, void *v, loff_t *pos);
>  void ima_policy_stop(struct seq_file *m, void *v);
> diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
> index 2dcc5a8c585a..fe3dce8fb939 100644
> --- a/security/integrity/ima/ima_policy.c
> +++ b/security/integrity/ima/ima_policy.c
> @@ -1889,6 +1889,20 @@ void ima_delete_rules(struct ima_namespace *ns)
>  	}
>  }
>  
> +/**
> + * ima_free_policy_rules - free all policy rules
> + * @ns: IMA namespace that has the policy
> + */
> +void ima_free_policy_rules(struct ima_namespace *ns)
> +{
> +	struct ima_rule_entry *entry, *tmp;
> +
> +	list_for_each_entry_safe(entry, tmp, &ns->ima_policy_rules, list) {
> +		list_del(&entry->list);
> +		ima_free_rule(entry);
> +	}
> +}
> +

The first time a policy is loaded, the policy rules pivot
from ima_default_rules to the custom rules.  When this happens, the
architecture specific policy rules are freed.  Here too, if a custom
policy isn't already loaded, the architecture specific rules stored as
an array need to be freed.  Refer to the comment in
ima_update_policy().

>  #define __ima_hook_stringify(func, str)	(#func),
>  
>  const char *const func_tokens[] = {

-- 
thanks,

Mimi