Smack: allow multiple labels in onlycap
Smack onlycap allows limiting of CAP_MAC_ADMIN and CAP_MAC_OVERRIDE to
processes running with the configured label. But having single privileged
label is not enough in some real use cases. On a complex system like Tizen,
there maybe few programs that need to configure Smack policy in run-time
and running them all with a single label is not always practical.
This patch extends onlycap feature for multiple labels. They are configured
in the same smackfs "onlycap" interface, separated by spaces.
Signed-off-by: Rafal Krypa <r.krypa@samsung.com>
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index 408e20b..00f6b38 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -617,3 +617,44 @@
rcu_read_unlock();
return &smack_known_invalid;
}
+
+/*
+ * Unless a process is running with one of these labels
+ * even having CAP_MAC_OVERRIDE isn't enough to grant
+ * privilege to violate MAC policy. If no labels are
+ * designated (the empty list case) capabilities apply to
+ * everyone.
+ */
+LIST_HEAD(smack_onlycap_list);
+DEFINE_MUTEX(smack_onlycap_lock);
+
+/*
+ * Is the task privileged and allowed to be privileged
+ * by the onlycap rule.
+ *
+ * Returns 1 if the task is allowed to be privileged, 0 if it's not.
+ */
+int smack_privileged(int cap)
+{
+ struct smack_known *skp = smk_of_current();
+ struct smack_onlycap *sop;
+
+ if (!capable(cap))
+ return 0;
+
+ rcu_read_lock();
+ if (list_empty(&smack_onlycap_list)) {
+ rcu_read_unlock();
+ return 1;
+ }
+
+ list_for_each_entry_rcu(sop, &smack_onlycap_list, list) {
+ if (sop->smk_label == skp) {
+ rcu_read_unlock();
+ return 1;
+ }
+ }
+ rcu_read_unlock();
+
+ return 0;
+}