mirror of
https://github.com/torvalds/linux.git
synced 2024-12-15 07:33:56 +00:00
49 lines
2.2 KiB
Plaintext
49 lines
2.2 KiB
Plaintext
|
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, 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.
|