NetLabel: Add secid token support to the NetLabel secattr struct

This patch adds support to the NetLabel LSM secattr struct for a secid token
and a type field, paving the way for full LSM/SELinux context support and
"static" or "fallback" labels.  In addition, this patch adds a fair amount
of documentation to the core NetLabel structures used as part of the
NetLabel kernel API.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/security/selinux/ss/mls.c b/security/selinux/ss/mls.c
index 3bbcb53..feaf0a5 100644
--- a/security/selinux/ss/mls.c
+++ b/security/selinux/ss/mls.c
@@ -562,7 +562,7 @@
 	if (!selinux_mls_enabled)
 		return;
 
-	secattr->mls_lvl = context->range.level[0].sens - 1;
+	secattr->attr.mls.lvl = context->range.level[0].sens - 1;
 	secattr->flags |= NETLBL_SECATTR_MLS_LVL;
 }
 
@@ -582,7 +582,7 @@
 	if (!selinux_mls_enabled)
 		return;
 
-	context->range.level[0].sens = secattr->mls_lvl + 1;
+	context->range.level[0].sens = secattr->attr.mls.lvl + 1;
 	context->range.level[1].sens = context->range.level[0].sens;
 }
 
@@ -605,8 +605,8 @@
 		return 0;
 
 	rc = ebitmap_netlbl_export(&context->range.level[0].cat,
-				   &secattr->mls_cat);
-	if (rc == 0 && secattr->mls_cat != NULL)
+				   &secattr->attr.mls.cat);
+	if (rc == 0 && secattr->attr.mls.cat != NULL)
 		secattr->flags |= NETLBL_SECATTR_MLS_CAT;
 
 	return rc;
@@ -633,7 +633,7 @@
 		return 0;
 
 	rc = ebitmap_netlbl_import(&context->range.level[0].cat,
-				   secattr->mls_cat);
+				   secattr->attr.mls.cat);
 	if (rc != 0)
 		goto import_netlbl_cat_failure;