Re: [PATCH v9 16/23] ima: Implement ima_free_policy_rules() for freeing of an ima_namespace

Stefan Berger
2022-01-31T18:57:25Z

On 1/28/22 09:02, Mimi Zohar wrote:
> Hi Stefan,
>
> On Tue, 2022-01-25 at 17:46 -0500, Stefan Berger wrote:
>> From: Stefan Berger <stefanb@linux.ibm.com>
>>
>> Implement ima_free_policy_rules() that is needed when an ima_namespace
>> is freed.
>>
>> Only reset temp_ima_appraise when using init_ima_ns.
> Instead of having to walk the policy rules to know if there are any
> "appraise" rules, the ima_appraise flag is set. For now, only reset
> temp_ima_appraise flag on failed policy rule updates for init_ima_ns.

Ok, I am taking this whole text.

>
>> Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
>>
>> ---
>> v9:
>> - Only reset temp_ima_appraise when using init_ima_ns.
>> ---
>> security/integrity/ima/ima.h | 1 +
>> security/integrity/ima/ima_policy.c | 20 +++++++++++++++++++-
>> 2 files changed, 20 insertions(+), 1 deletion(-)
>>
>> 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 e8140e73d80b..47f2d1b5d156 100644
>> --- a/security/integrity/ima/ima_policy.c
>> +++ b/security/integrity/ima/ima_policy.c
>> @@ -1880,13 +1880,31 @@ void ima_delete_rules(struct ima_namespace *ns)
>> {
>> struct ima_rule_entry *entry, *tmp;
>>
>> - temp_ima_appraise = 0;
>> + if (ns == &init_ima_ns)
>> + temp_ima_appraise = 0;
>> +
>> list_for_each_entry_safe(entry, tmp, &ns->ima_temp_rules, list) {
>> list_del(&entry->list);
>> ima_free_rule(entry);
>> }
>> }
>>
>> +/**
>> + * 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;
>> +
>> + ima_delete_rules(ns);
> When the IMA policy is being extended, new rules are temporarily added
> to the ima_temp_rules list. If the entire set of rules being added are
> valid, they're appended to the tail.
>
> There shouldn't be any rules on the ima_temp_rules list unless the
> policy is currently being extended. Is that possible at this point?

Actually, no. Nothing can be left. I am removing this call.

I wonder whether to split this patch into into two patches?

>
>> +
>> + list_for_each_entry_safe(entry, tmp, &ns->ima_policy_rules, list) {
>> + list_del(&entry->list);
>> + ima_free_rule(entry);
>> + }
>> +}
>> +
>> #define __ima_hook_stringify(func, str) (#func),
>>
>> const char *const func_tokens[] = {
> thanks,
>
> Mimi
>