mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-24 03:24:55 +08:00
593733ab80
Convert netlabel documentation to ReST. This was trivial: just add proper title markups. At its new index.rst, let's add a :orphan: while this is not linked to the main index.rst file, in order to avoid build warnings. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Acked-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
54 lines
2.5 KiB
ReStructuredText
54 lines
2.5 KiB
ReStructuredText
========================================
|
|
NetLabel Linux Security Module Interface
|
|
========================================
|
|
|
|
Paul Moore, paul.moore@hp.com
|
|
|
|
May 17, 2006
|
|
|
|
Overview
|
|
========
|
|
|
|
NetLabel is a mechanism which can set and retrieve security attributes from
|
|
network packets. It is intended to be used by LSM developers who want to make
|
|
use of a common code base for several different packet labeling protocols.
|
|
The NetLabel security module API is defined in 'include/net/netlabel.h' but a
|
|
brief overview is given below.
|
|
|
|
NetLabel Security Attributes
|
|
============================
|
|
|
|
Since NetLabel supports multiple different packet labeling protocols and LSMs
|
|
it uses the concept of security attributes to refer to the packet's security
|
|
labels. The NetLabel security attributes are defined by the
|
|
'netlbl_lsm_secattr' structure in the NetLabel header file. Internally the
|
|
NetLabel subsystem converts the security attributes to and from the correct
|
|
low-level packet label depending on the NetLabel build time and run time
|
|
configuration. It is up to the LSM developer to translate the NetLabel
|
|
security attributes into whatever security identifiers are in use for their
|
|
particular LSM.
|
|
|
|
NetLabel LSM Protocol Operations
|
|
================================
|
|
|
|
These are the functions which allow the LSM developer to manipulate the labels
|
|
on outgoing packets as well as read the labels on incoming packets. Functions
|
|
exist to operate both on sockets as well as the sk_buffs directly. These high
|
|
level functions are translated into low level protocol operations based on how
|
|
the administrator has configured the NetLabel subsystem.
|
|
|
|
NetLabel Label Mapping Cache Operations
|
|
=======================================
|
|
|
|
Depending on the exact configuration, translation between the network packet
|
|
label and the internal LSM security identifier can be time consuming. The
|
|
NetLabel label mapping cache is a caching mechanism which can be used to
|
|
sidestep much of this overhead once a mapping has been established. Once the
|
|
LSM has received a packet, used NetLabel to decode its security attributes,
|
|
and translated the security attributes into a LSM internal identifier the LSM
|
|
can use the NetLabel caching functions to associate the LSM internal
|
|
identifier with the network packet's label. This means that in the future
|
|
when a incoming packet matches a cached value not only are the internal
|
|
NetLabel translation mechanisms bypassed but the LSM translation mechanisms are
|
|
bypassed as well which should result in a significant reduction in overhead.
|