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

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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@xxxxxxxxxxxxx>

---
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[] = {



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