diff mbox series

[v10,16/27] ima: Implement ima_free_policy_rules() for freeing of an ima_namespace

Message ID 20220201203735.164593-17-stefanb@linux.ibm.com (mailing list archive)
State New, archived
Headers show
Series ima: Namespace IMA with audit support in IMA-ns | expand

Commit Message

Stefan Berger Feb. 1, 2022, 8:37 p.m. UTC
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(+)

Comments

Mimi Zohar Feb. 18, 2022, 5:09 p.m. UTC | #1
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[] = {
Stefan Berger Feb. 18, 2022, 7:38 p.m. UTC | #2
On 2/18/22 12:09, Mimi Zohar wrote:
> 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().

Right. So here's how it's done (before arch_policy_entry was moved into 
ima_namespace).

         /*
          * IMA architecture specific policy rules are specified
          * as strings and converted to an array of ima_entry_rules
          * on boot.  After loading a custom policy, free the
          * architecture specific rules stored as an array.
          */
         kfree(arch_policy_entry);


So, I now added kfree(ns->arch_policy_entry).

Thanks.

    Stefan

>
>>   #define __ima_hook_stringify(func, str)	(#func),
>>   
>>   const char *const func_tokens[] = {
Mimi Zohar Feb. 18, 2022, 8:04 p.m. UTC | #3
On Fri, 2022-02-18 at 14:38 -0500, Stefan Berger wrote:
> On 2/18/22 12:09, Mimi Zohar wrote:
> > 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.

ima_free_policy_rules() isn't free all the rules, just the custom
policy rules.  I would update the patch description as:

Implement ima_free_policy_rules() to free the custom policy rules, when
...

Otherwise,

Reviewd-by: Mimi Zohar <zohar@linux.ibm.com>

> >>
> >> 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().
> 
> Right. So here's how it's done (before arch_policy_entry was moved into 
> ima_namespace).
> 
>          /*
>           * IMA architecture specific policy rules are specified
>           * as strings and converted to an array of ima_entry_rules
>           * on boot.  After loading a custom policy, free the
>           * architecture specific rules stored as an array.
>           */
>          kfree(arch_policy_entry);
> 
> 
> So, I now added kfree(ns->arch_policy_entry).

Yes, that is fine.
diff mbox series

Patch

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