[apparmor] [PATCH] APPARMOR: Fix NULL Pointer dereference while __add_new_profile

[wzt.wzt at gmail.com]

In aa_replace_profiles(), if __lookup_parent() path failed, policy is set 
to NULL and goto audit label, old_profile and rename_profile are both NULL,
__add_new_profile is called, the parameter policy is NULL, it will cause
NULL pointer dereference via __list_add_profile(&policy->profiles, profile);

Signed-off-by: Zhitong Wang <zhitong.wangzt at alibaba-inc.com>

---
 security/apparmor/policy.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/security/apparmor/policy.c b/security/apparmor/policy.c
index 52cc865..832d9e9 100644
--- a/security/apparmor/policy.c
+++ b/security/apparmor/policy.c
@@ -940,6 +940,8 @@ static int replacement_allowed(struct aa_profile *profile, int noreplace,
 static void __add_new_profile(struct aa_namespace *ns, struct aa_policy *policy,
 			      struct aa_profile *profile)
 {
+	if (!policy)
+		return ;
 	if (policy != &ns->base)
 		/* released on profile replacement or free_profile */
 		profile->parent = aa_get_profile((struct aa_profile *) policy);
-- 
1.6.5.3