apparmor: fix module parameters can be changed after policy is locked
the policy_lock parameter is a one way switch that prevents policy
from being further modified. Unfortunately some of the module parameters
can effectively modify policy by turning off enforcement.
split policy_admin_capable into a view check and a full admin check,
and update the admin check to test the policy_lock parameter.
Signed-off-by: John Johansen <john.johansen@canonical.com>
diff --git a/security/apparmor/policy.c b/security/apparmor/policy.c
index 7807125..179e68d 100644
--- a/security/apparmor/policy.c
+++ b/security/apparmor/policy.c
@@ -918,6 +918,22 @@
&sa, NULL);
}
+bool policy_view_capable(void)
+{
+ struct user_namespace *user_ns = current_user_ns();
+ bool response = false;
+
+ if (ns_capable(user_ns, CAP_MAC_ADMIN))
+ response = true;
+
+ return response;
+}
+
+bool policy_admin_capable(void)
+{
+ return policy_view_capable() && !aa_g_lock_policy;
+}
+
/**
* aa_may_manage_policy - can the current task manage policy
* @op: the policy manipulation operation being done
@@ -932,7 +948,7 @@
return 0;
}
- if (!capable(CAP_MAC_ADMIN)) {
+ if (!policy_admin_capable()) {
audit_policy(op, GFP_KERNEL, NULL, "not policy admin", -EACCES);
return 0;
}