[NetLabel]: documentation

Documentation for the NetLabel system, this includes a basic overview
of how NetLabel works, how LSM developers can integrate it into their
favorite LSM, as well as documentation on the CIPSO related sysctl
variables.  Also, due to the difficulty of finding expired IETF
drafts, I am including the IETF CIPSO draft that is the basis of the
NetLabel CIPSO implementation.

Signed-off-by: Paul Moore <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

CREDITS

@@ -2384,6 +2384,13 @@ N: Thomas Molina
 E: [email protected]
 D: bug fixes, documentation, minor hackery
 
+N: Paul Moore
+E: [email protected]
+D: NetLabel author
+S: Hewlett-Packard
+S: 110 Spit Brook Road
+S: Nashua, NH 03062
+
 N: James Morris
 E: [email protected]
 W: http://namei.org/

Documentation/00-INDEX

@@ -184,6 +184,8 @@ mtrr.txt
 	- how to use PPro Memory Type Range Registers to increase performance.
 nbd.txt
 	- info on a TCP implementation of a network block device.
+netlabel/
+	- directory with information on the NetLabel subsystem.
 networking/
 	- directory with info on various aspects of networking with Linux.
 nfsroot.txt

Documentation/netlabel/00-INDEX

@@ -0,0 +1,10 @@
+00-INDEX
+	- this file.
+cipso_ipv4.txt
+	- documentation on the IPv4 CIPSO protocol engine.
+draft-ietf-cipso-ipsecurity-01.txt
+	- IETF draft of the CIPSO protocol, dated 16 July 1992.
+introduction.txt
+	- NetLabel introduction, READ THIS FIRST.
+lsm_interface.txt
+	- documentation on the NetLabel kernel security module API.

Documentation/netlabel/cipso_ipv4.txt

@@ -0,0 +1,48 @@
+NetLabel CIPSO/IPv4 Protocol Engine
+==============================================================================
+Paul Moore, [email protected]
+
+May 17, 2006
+
+ * Overview
+
+The NetLabel CIPSO/IPv4 protocol engine is based on the IETF Commercial IP
+Security Option (CIPSO) draft from July 16, 1992.  A copy of this draft can be
+found in this directory, consult '00-INDEX' for the filename.  While the IETF
+draft never made it to an RFC standard it has become a de-facto standard for
+labeled networking and is used in many trusted operating systems.
+
+ * Outbound Packet Processing
+
+The CIPSO/IPv4 protocol engine applies the CIPSO IP option to packets by
+adding the CIPSO label to the socket.  This causes all packets leaving the
+system through the socket to have the CIPSO IP option applied.  The socket's
+CIPSO label can be changed at any point in time, however, it is recommended
+that it is set upon the socket's creation.  The LSM can set the socket's CIPSO
+label by using the NetLabel security module API; if the NetLabel "domain" is
+configured to use CIPSO for packet labeling then a CIPSO IP option will be
+generated and attached to the socket.
+
+ * Inbound Packet Processing
+
+The CIPSO/IPv4 protocol engine validates every CIPSO IP option it finds at the
+IP layer without any special handling required by the LSM.  However, in order
+to decode and translate the CIPSO label on the packet the LSM must use the
+NetLabel security module API to extract the security attributes of the packet.
+This is typically done at the socket layer using the 'socket_sock_rcv_skb()'
+LSM hook.
+
+ * Label Translation
+
+The CIPSO/IPv4 protocol engine contains a mechanism to translate CIPSO security
+attributes such as sensitivity level and category to values which are
+appropriate for the host.  These mappings are defined as part of a CIPSO
+Domain Of Interpretation (DOI) definition and are configured through the
+NetLabel user space communication layer.  Each DOI definition can have a
+different security attribute mapping table.
+
+ * Label Translation Cache
+
+The NetLabel system provides a framework for caching security attribute
+mappings from the network labels to the corresponding LSM identifiers.  The
+CIPSO/IPv4 protocol engine supports this caching mechanism.