Merge tag 'docs-5.3' of git://git.lwn.net/linux

Pull Documentation updates from Jonathan Corbet:
 "It's been a relatively busy cycle for docs:

   - A fair pile of RST conversions, many from Mauro. These create more
     than the usual number of simple but annoying merge conflicts with
     other trees, unfortunately. He has a lot more of these waiting on
     the wings that, I think, will go to you directly later on.

   - A new document on how to use merges and rebases in kernel repos,
     and one on Spectre vulnerabilities.

   - Various improvements to the build system, including automatic
     markup of function() references because some people, for reasons I
     will never understand, were of the opinion that
     :c:func:``function()`` is unattractive and not fun to type.

   - We now recommend using sphinx 1.7, but still support back to 1.4.

   - Lots of smaller improvements, warning fixes, typo fixes, etc"

* tag 'docs-5.3' of git://git.lwn.net/linux: (129 commits)
  docs: automarkup.py: ignore exceptions when seeking for xrefs
  docs: Move binderfs to admin-guide
  Disable Sphinx SmartyPants in HTML output
  doc: RCU callback locks need only _bh, not necessarily _irq
  docs: format kernel-parameters -- as code
  Doc : doc-guide : Fix a typo
  platform: x86: get rid of a non-existent document
  Add the RCU docs to the core-api manual
  Documentation: RCU: Add TOC tree hooks
  Documentation: RCU: Rename txt files to rst
  Documentation: RCU: Convert RCU UP systems to reST
  Documentation: RCU: Convert RCU linked list to reST
  Documentation: RCU: Convert RCU basic concepts to reST
  docs: filesystems: Remove uneeded .rst extension on toctables
  scripts/sphinx-pre-install: fix out-of-tree build
  docs: zh_CN: submitting-drivers.rst: Remove a duplicated Documentation/
  Documentation: PGP: update for newer HW devices
  Documentation: Add section about CPU vulnerabilities for Spectre
  Documentation: platform: Delete x86-laptop-drivers.txt
  docs: Note that :c:func: should no longer be used
  ...

1 files changed, 53 insertions, 0 deletions

diff --git a/Documentation/netlabel/lsm_interface.rst b/Documentation/netlabel/lsm_interface.rst
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+========================================
+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.