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diff --git a/Documentation/netlabel/cipso_ipv4.rst b/Documentation/netlabel/cipso_ipv4.rst new file mode 100644 index 000000000..cbd3f3231 --- /dev/null +++ b/Documentation/netlabel/cipso_ipv4.rst @@ -0,0 +1,56 @@ +=================================== +NetLabel CIPSO/IPv4 Protocol Engine +=================================== + +Paul Moore, paul.moore@hp.com + +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 +(draft-ietf-cipso-ipsecurity-01.txt). 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. |