[PATCH 1/3] ima: Have the LSM free its audit rule

[gouhao@uniontech.com]

From: Tyler Hicks <tyhicks@linux.microsoft.com>

commit 9ff8a616dfab96a4fa0ddd36190907dc68886d9b upstream.

Ask the LSM to free its audit rule rather than directly calling kfree().
Both AppArmor and SELinux do additional work in their audit_rule_free()
hooks. Fix memory leaks by allowing the LSMs to perform necessary work.

Fixes: b16942455193 ("ima: use the lsm policy update notifier")
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Cc: Janne Karhunen <janne.karhunen@gmail.com>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Cc: <stable@vger.kernel.org> # 4.19+
Signed-off-by: Gou Hao <gouhao@uniontech.com>
---
 security/integrity/ima/ima.h        | 5 +++++
 security/integrity/ima/ima_policy.c | 4 +++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index d12b07eb3a58..e2916b115b93 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -298,6 +298,7 @@ static inline int ima_read_xattr(struct dentry *dentry,
 #ifdef CONFIG_IMA_LSM_RULES
 
 #define security_filter_rule_init security_audit_rule_init
+#define security_filter_rule_free security_audit_rule_free
 #define security_filter_rule_match security_audit_rule_match
 
 #else
@@ -308,6 +309,10 @@ static inline int security_filter_rule_init(u32 field, u32 op, char *rulestr,
 	return -EINVAL;
 }
 
+static inline void security_filter_rule_free(void *lsmrule)
+{
+}
+
 static inline int security_filter_rule_match(u32 secid, u32 field, u32 op,
 					     void *lsmrule,
 					     struct audit_context *actx)
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 2d5a3daa02f9..733efc06d3c1 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -1044,8 +1044,10 @@ void ima_delete_rules(void)
 
 	temp_ima_appraise = 0;
 	list_for_each_entry_safe(entry, tmp, &ima_temp_rules, list) {
-		for (i = 0; i < MAX_LSM_RULES; i++)
+		for (i = 0; i < MAX_LSM_RULES; i++) {
+			security_filter_rule_free(entry->lsm[i].rule);
 			kfree(entry->lsm[i].args_p);
+		}
 
 		list_del(&entry->list);
 		kfree(entry);
-- 
2.20.1