Message-ID: <b20824f2-8881-7e0d-735d-d8c9010c78e9@schaufler-ca.com>
Date:   Mon, 15 May 2017 07:13:21 -0700
From:   Casey Schaufler <casey@...aufler-ca.com>
To:     Kees Cook <keescook@...omium.org>, Jonathan Corbet <corbet@....net>
Cc:     John Johansen <john.johansen@...onical.com>,
        Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>,
        Paul Moore <paul@...l-moore.com>,
        David Howells <dhowells@...hat.com>,
        Mimi Zohar <zohar@...ux.vnet.ibm.com>,
        James Morris <james.l.morris@...cle.com>,
        Tyler Hicks <tyhicks@...onical.com>,
        David Safford <safford@...ibm.com>, linux-doc@...r.kernel.org,
        linux-security-module@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 13/17] doc: ReSTify Smack.txt

On 5/13/2017 4:51 AM, Kees Cook wrote:
> Adjusts for ReST markup and moves under LSM admin guide.
>
> Cc: Casey Schaufler <casey@...aufler-ca.com>
> Signed-off-by: Kees Cook <keescook@...omium.org>

Acked-by: Casey Schaufler <casey@...aufler-ca.com>

Thank you.

> ---
>  .../Smack.txt => admin-guide/LSM/Smack.rst}        | 273 ++++++++++++++-------
>  Documentation/admin-guide/LSM/index.rst            |   1 +
>  Documentation/security/00-INDEX                    |   2 -
>  MAINTAINERS                                        |   2 +-
>  4 files changed, 191 insertions(+), 87 deletions(-)
>  rename Documentation/{security/Smack.txt => admin-guide/LSM/Smack.rst} (85%)
>
> diff --git a/Documentation/security/Smack.txt b/Documentation/admin-guide/LSM/Smack.rst
> similarity index 85%
> rename from Documentation/security/Smack.txt
> rename to Documentation/admin-guide/LSM/Smack.rst
> index 945cc633d883..6a5826a13aea 100644
> --- a/Documentation/security/Smack.txt
> +++ b/Documentation/admin-guide/LSM/Smack.rst
> @@ -1,3 +1,6 @@
> +=====
> +Smack
> +=====
>  
>  
>      "Good for you, you've decided to clean the elevator!"
> @@ -14,6 +17,7 @@ available to determine which is best suited to the problem
>  at hand.
>  
>  Smack consists of three major components:
> +
>      - The kernel
>      - Basic utilities, which are helpful but not required
>      - Configuration data
> @@ -39,16 +43,24 @@ The current git repository for Smack user space is:
>  This should make and install on most modern distributions.
>  There are five commands included in smackutil:
>  
> -chsmack    - display or set Smack extended attribute values
> -smackctl   - load the Smack access rules
> -smackaccess - report if a process with one label has access
> -              to an object with another
> +chsmack:
> +	display or set Smack extended attribute values
> +
> +smackctl:
> +	load the Smack access rules
> +
> +smackaccess:
> +	report if a process with one label has access
> +	to an object with another
>  
>  These two commands are obsolete with the introduction of
>  the smackfs/load2 and smackfs/cipso2 interfaces.
>  
> -smackload  - properly formats data for writing to smackfs/load
> -smackcipso - properly formats data for writing to smackfs/cipso
> +smackload:
> +	properly formats data for writing to smackfs/load
> +
> +smackcipso:
> +	properly formats data for writing to smackfs/cipso
>  
>  In keeping with the intent of Smack, configuration data is
>  minimal and not strictly required. The most important
> @@ -56,15 +68,15 @@ configuration step is mounting the smackfs pseudo filesystem.
>  If smackutil is installed the startup script will take care
>  of this, but it can be manually as well.
>  
> -Add this line to /etc/fstab:
> +Add this line to ``/etc/fstab``::
>  
>      smackfs /sys/fs/smackfs smackfs defaults 0 0
>  
> -The /sys/fs/smackfs directory is created by the kernel.
> +The ``/sys/fs/smackfs`` directory is created by the kernel.
>  
>  Smack uses extended attributes (xattrs) to store labels on filesystem
>  objects. The attributes are stored in the extended attribute security
> -name space. A process must have CAP_MAC_ADMIN to change any of these
> +name space. A process must have ``CAP_MAC_ADMIN`` to change any of these
>  attributes.
>  
>  The extended attributes that Smack uses are:
> @@ -73,14 +85,17 @@ SMACK64
>  	Used to make access control decisions. In almost all cases
>  	the label given to a new filesystem object will be the label
>  	of the process that created it.
> +
>  SMACK64EXEC
>  	The Smack label of a process that execs a program file with
>  	this attribute set will run with this attribute's value.
> +
>  SMACK64MMAP
>  	Don't allow the file to be mmapped by a process whose Smack
>  	label does not allow all of the access permitted to a process
>  	with the label contained in this attribute. This is a very
>  	specific use case for shared libraries.
> +
>  SMACK64TRANSMUTE
>  	Can only have the value "TRUE". If this attribute is present
>  	on a directory when an object is created in the directory and
> @@ -89,27 +104,29 @@ SMACK64TRANSMUTE
>  	gets the label of the directory instead of the label of the
>  	creating process. If the object being created is a directory
>  	the SMACK64TRANSMUTE attribute is set as well.
> +
>  SMACK64IPIN
>  	This attribute is only available on file descriptors for sockets.
>  	Use the Smack label in this attribute for access control
>  	decisions on packets being delivered to this socket.
> +
>  SMACK64IPOUT
>  	This attribute is only available on file descriptors for sockets.
>  	Use the Smack label in this attribute for access control
>  	decisions on packets coming from this socket.
>  
> -There are multiple ways to set a Smack label on a file:
> +There are multiple ways to set a Smack label on a file::
>  
>      # attr -S -s SMACK64 -V "value" path
>      # chsmack -a value path
>  
>  A process can see the Smack label it is running with by
> -reading /proc/self/attr/current. A process with CAP_MAC_ADMIN
> +reading ``/proc/self/attr/current``. A process with ``CAP_MAC_ADMIN``
>  can set the process Smack by writing there.
>  
>  Most Smack configuration is accomplished by writing to files
>  in the smackfs filesystem. This pseudo-filesystem is mounted
> -on /sys/fs/smackfs.
> +on ``/sys/fs/smackfs``.
>  
>  access
>  	Provided for backward compatibility. The access2 interface
> @@ -120,6 +137,7 @@ access
>  	this file. The next read will indicate whether the access
>  	would be permitted. The text will be either "1" indicating
>  	access, or "0" indicating denial.
> +
>  access2
>  	This interface reports whether a subject with the specified
>  	Smack label has a particular access to an object with a
> @@ -127,13 +145,17 @@ access2
>  	this file. The next read will indicate whether the access
>  	would be permitted. The text will be either "1" indicating
>  	access, or "0" indicating denial.
> +
>  ambient
>  	This contains the Smack label applied to unlabeled network
>  	packets.
> +
>  change-rule
>  	This interface allows modification of existing access control rules.
> -	The format accepted on write is:
> +	The format accepted on write is::
> +
>  		"%s %s %s %s"
> +
>  	where the first string is the subject label, the second the
>  	object label, the third the access to allow and the fourth the
>  	access to deny. The access strings may contain only the characters
> @@ -141,47 +163,63 @@ change-rule
>  	modified by enabling the permissions in the third string and disabling
>  	those in the fourth string. If there is no such rule it will be
>  	created using the access specified in the third and the fourth strings.
> +
>  cipso
>  	Provided for backward compatibility. The cipso2 interface
>  	is preferred and should be used instead.
>  	This interface allows a specific CIPSO header to be assigned
> -	to a Smack label. The format accepted on write is:
> +	to a Smack label. The format accepted on write is::
> +
>  		"%24s%4d%4d"["%4d"]...
> +
>  	The first string is a fixed Smack label. The first number is
>  	the level to use. The second number is the number of categories.
> -	The following numbers are the categories.
> -	"level-3-cats-5-19          3   2   5  19"
> +	The following numbers are the categories::
> +
> +		"level-3-cats-5-19          3   2   5  19"
> +
>  cipso2
>  	This interface allows a specific CIPSO header to be assigned
> -	to a Smack label. The format accepted on write is:
> -	"%s%4d%4d"["%4d"]...
> +	to a Smack label. The format accepted on write is::
> +
> +		"%s%4d%4d"["%4d"]...
> +
>  	The first string is a long Smack label. The first number is
>  	the level to use. The second number is the number of categories.
> -	The following numbers are the categories.
> -	"level-3-cats-5-19   3   2   5  19"
> +	The following numbers are the categories::
> +
> +		"level-3-cats-5-19   3   2   5  19"
> +
>  direct
>  	This contains the CIPSO level used for Smack direct label
>  	representation in network packets.
> +
>  doi
>  	This contains the CIPSO domain of interpretation used in
>  	network packets.
> +
>  ipv6host
>  	This interface allows specific IPv6 internet addresses to be
>  	treated as single label hosts. Packets are sent to single
>  	label hosts only from processes that have Smack write access
>  	to the host label. All packets received from single label hosts
> -	are given the specified label. The format accepted on write is:
> +	are given the specified label. The format accepted on write is::
> +
>  		"%h:%h:%h:%h:%h:%h:%h:%h label" or
>  		"%h:%h:%h:%h:%h:%h:%h:%h/%d label".
> +
>  	The "::" address shortcut is not supported.
>  	If label is "-DELETE" a matched entry will be deleted.
> +
>  load
>  	Provided for backward compatibility. The load2 interface
>  	is preferred and should be used instead.
>  	This interface allows access control rules in addition to
>  	the system defined rules to be specified. The format accepted
> -	on write is:
> +	on write is::
> +
>  		"%24s%24s%5s"
> +
>  	where the first string is the subject label, the second the
>  	object label, and the third the requested access. The access
>  	string may contain only the characters "rwxat-", and specifies
> @@ -189,17 +227,21 @@ load
>  	permissions that are not allowed. The string "r-x--" would
>  	specify read and execute access. Labels are limited to 23
>  	characters in length.
> +
>  load2
>  	This interface allows access control rules in addition to
>  	the system defined rules to be specified. The format accepted
> -	on write is:
> +	on write is::
> +
>  		"%s %s %s"
> +
>  	where the first string is the subject label, the second the
>  	object label, and the third the requested access. The access
>  	string may contain only the characters "rwxat-", and specifies
>  	which sort of access is allowed. The "-" is a placeholder for
>  	permissions that are not allowed. The string "r-x--" would
>  	specify read and execute access.
> +
>  load-self
>  	Provided for backward compatibility. The load-self2 interface
>  	is preferred and should be used instead.
> @@ -208,66 +250,83 @@ load-self
>  	otherwise be permitted, and are intended to provide additional
>  	restrictions on the process. The format is the same as for
>  	the load interface.
> +
>  load-self2
>  	This interface allows process specific access rules to be
>  	defined. These rules are only consulted if access would
>  	otherwise be permitted, and are intended to provide additional
>  	restrictions on the process. The format is the same as for
>  	the load2 interface.
> +
>  logging
>  	This contains the Smack logging state.
> +
>  mapped
>  	This contains the CIPSO level used for Smack mapped label
>  	representation in network packets.
> +
>  netlabel
>  	This interface allows specific internet addresses to be
>  	treated as single label hosts. Packets are sent to single
>  	label hosts without CIPSO headers, but only from processes
>  	that have Smack write access to the host label. All packets
>  	received from single label hosts are given the specified
> -	label. The format accepted on write is:
> +	label. The format accepted on write is::
> +
>  		"%d.%d.%d.%d label" or "%d.%d.%d.%d/%d label".
> +
>  	If the label specified is "-CIPSO" the address is treated
>  	as a host that supports CIPSO headers.
> +
>  onlycap
>  	This contains labels processes must have for CAP_MAC_ADMIN
> -	and CAP_MAC_OVERRIDE to be effective. If this file is empty
> +	and ``CAP_MAC_OVERRIDE`` to be effective. If this file is empty
>  	these capabilities are effective at for processes with any
>  	label. The values are set by writing the desired labels, separated
>  	by spaces, to the file or cleared by writing "-" to the file.
> +
>  ptrace
>  	This is used to define the current ptrace policy
> -	0 - default: this is the policy that relies on Smack access rules.
> -	    For the PTRACE_READ a subject needs to have a read access on
> -	    object. For the PTRACE_ATTACH a read-write access is required.
> -	1 - exact: this is the policy that limits PTRACE_ATTACH. Attach is
> +
> +	0 - default:
> +	    this is the policy that relies on Smack access rules.
> +	    For the ``PTRACE_READ`` a subject needs to have a read access on
> +	    object. For the ``PTRACE_ATTACH`` a read-write access is required.
> +
> +	1 - exact:
> +	    this is the policy that limits ``PTRACE_ATTACH``. Attach is
>  	    only allowed when subject's and object's labels are equal.
> -	    PTRACE_READ is not affected. Can be overridden with CAP_SYS_PTRACE.
> -	2 - draconian: this policy behaves like the 'exact' above with an
> -	    exception that it can't be overridden with CAP_SYS_PTRACE.
> +	    ``PTRACE_READ`` is not affected. Can be overridden with ``CAP_SYS_PTRACE``.
> +
> +	2 - draconian:
> +	    this policy behaves like the 'exact' above with an
> +	    exception that it can't be overridden with ``CAP_SYS_PTRACE``.
> +
>  revoke-subject
>  	Writing a Smack label here sets the access to '-' for all access
>  	rules with that subject label.
> +
>  unconfined
> -	If the kernel is configured with CONFIG_SECURITY_SMACK_BRINGUP
> -	a process with CAP_MAC_ADMIN can write a label into this interface.
> +	If the kernel is configured with ``CONFIG_SECURITY_SMACK_BRINGUP``
> +	a process with ``CAP_MAC_ADMIN`` can write a label into this interface.
>  	Thereafter, accesses that involve that label will be logged and
>  	the access permitted if it wouldn't be otherwise. Note that this
>  	is dangerous and can ruin the proper labeling of your system.
>  	It should never be used in production.
> +
>  relabel-self
>  	This interface contains a list of labels to which the process can
> -	transition to, by writing to /proc/self/attr/current.
> +	transition to, by writing to ``/proc/self/attr/current``.
>  	Normally a process can change its own label to any legal value, but only
> -	if it has CAP_MAC_ADMIN. This interface allows a process without
> -	CAP_MAC_ADMIN to relabel itself to one of labels from predefined list.
> -	A process without CAP_MAC_ADMIN can change its label only once. When it
> +	if it has ``CAP_MAC_ADMIN``. This interface allows a process without
> +	``CAP_MAC_ADMIN`` to relabel itself to one of labels from predefined list.
> +	A process without ``CAP_MAC_ADMIN`` can change its label only once. When it
>  	does, this list will be cleared.
>  	The values are set by writing the desired labels, separated
>  	by spaces, to the file or cleared by writing "-" to the file.
>  
>  If you are using the smackload utility
> -you can add access rules in /etc/smack/accesses. They take the form:
> +you can add access rules in ``/etc/smack/accesses``. They take the form::
>  
>      subjectlabel objectlabel access
>  
> @@ -277,14 +336,14 @@ object with objectlabel. If there is no rule no access is allowed.
>  
>  Look for additional programs on http://schaufler-ca.com
>  
> -From the Smack Whitepaper:
> -
> -The Simplified Mandatory Access Control Kernel
> +The Simplified Mandatory Access Control Kernel (Whitepaper)
> +===========================================================
>  
>  Casey Schaufler
>  casey@...aufler-ca.com
>  
>  Mandatory Access Control
> +------------------------
>  
>  Computer systems employ a variety of schemes to constrain how information is
>  shared among the people and services using the machine. Some of these schemes
> @@ -297,6 +356,7 @@ access control mechanisms because you don't have a choice regarding the users
>  or programs that have access to pieces of data.
>  
>  Bell & LaPadula
> +---------------
>  
>  From the middle of the 1980's until the turn of the century Mandatory Access
>  Control (MAC) was very closely associated with the Bell & LaPadula security
> @@ -306,6 +366,7 @@ within the Capital Beltway and Scandinavian supercomputer centers but was
>  often sited as failing to address general needs.
>  
>  Domain Type Enforcement
> +-----------------------
>  
>  Around the turn of the century Domain Type Enforcement (DTE) became popular.
>  This scheme organizes users, programs, and data into domains that are
> @@ -316,6 +377,7 @@ necessary to provide a secure domain mapping leads to the scheme being
>  disabled or used in limited ways in the majority of cases.
>  
>  Smack
> +-----
>  
>  Smack is a Mandatory Access Control mechanism designed to provide useful MAC
>  while avoiding the pitfalls of its predecessors. The limitations of Bell &
> @@ -326,46 +388,55 @@ Enforcement and avoided by defining access controls in terms of the access
>  modes already in use.
>  
>  Smack Terminology
> +-----------------
>  
>  The jargon used to talk about Smack will be familiar to those who have dealt
>  with other MAC systems and shouldn't be too difficult for the uninitiated to
>  pick up. There are four terms that are used in a specific way and that are
>  especially important:
>  
> -	Subject: A subject is an active entity on the computer system.
> +  Subject:
> +	A subject is an active entity on the computer system.
>  	On Smack a subject is a task, which is in turn the basic unit
>  	of execution.
>  
> -	Object: An object is a passive entity on the computer system.
> +  Object:
> +	An object is a passive entity on the computer system.
>  	On Smack files of all types, IPC, and tasks can be objects.
>  
> -	Access: Any attempt by a subject to put information into or get
> +  Access:
> +	Any attempt by a subject to put information into or get
>  	information from an object is an access.
>  
> -	Label: Data that identifies the Mandatory Access Control
> +  Label:
> +	Data that identifies the Mandatory Access Control
>  	characteristics of a subject or an object.
>  
>  These definitions are consistent with the traditional use in the security
>  community. There are also some terms from Linux that are likely to crop up:
>  
> -	Capability: A task that possesses a capability has permission to
> +  Capability:
> +	A task that possesses a capability has permission to
>  	violate an aspect of the system security policy, as identified by
>  	the specific capability. A task that possesses one or more
>  	capabilities is a privileged task, whereas a task with no
>  	capabilities is an unprivileged task.
>  
> -	Privilege: A task that is allowed to violate the system security
> +  Privilege:
> +	A task that is allowed to violate the system security
>  	policy is said to have privilege. As of this writing a task can
>  	have privilege either by possessing capabilities or by having an
>  	effective user of root.
>  
>  Smack Basics
> +------------
>  
>  Smack is an extension to a Linux system. It enforces additional restrictions
>  on what subjects can access which objects, based on the labels attached to
>  each of the subject and the object.
>  
>  Labels
> +~~~~~~
>  
>  Smack labels are ASCII character strings. They can be up to 255 characters
>  long, but keeping them to twenty-three characters is recommended.
> @@ -377,7 +448,7 @@ contain unprintable characters, the "/" (slash), the "\" (backslash), the "'"
>  (quote) and '"' (double-quote) characters.
>  Smack labels cannot begin with a '-'. This is reserved for special options.
>  
> -There are some predefined labels:
> +There are some predefined labels::
>  
>  	_ 	Pronounced "floor", a single underscore character.
>  	^ 	Pronounced "hat", a single circumflex character.
> @@ -390,14 +461,18 @@ of a process will usually be assigned by the system initialization
>  mechanism.
>  
>  Access Rules
> +~~~~~~~~~~~~
>  
>  Smack uses the traditional access modes of Linux. These modes are read,
>  execute, write, and occasionally append. There are a few cases where the
>  access mode may not be obvious. These include:
>  
> -	Signals: A signal is a write operation from the subject task to
> +  Signals:
> +	A signal is a write operation from the subject task to
>  	the object task.
> -	Internet Domain IPC: Transmission of a packet is considered a
> +
> +  Internet Domain IPC:
> +	Transmission of a packet is considered a
>  	write operation from the source task to the destination task.
>  
>  Smack restricts access based on the label attached to a subject and the label
> @@ -417,6 +492,7 @@ order:
>  	7. Any other access is denied.
>  
>  Smack Access Rules
> +~~~~~~~~~~~~~~~~~~
>  
>  With the isolation provided by Smack access separation is simple. There are
>  many interesting cases where limited access by subjects to objects with
> @@ -427,8 +503,9 @@ be "born" highly classified. To accommodate such schemes Smack includes a
>  mechanism for specifying rules allowing access between labels.
>  
>  Access Rule Format
> +~~~~~~~~~~~~~~~~~~
>  
> -The format of an access rule is:
> +The format of an access rule is::
>  
>  	subject-label object-label access
>  
> @@ -446,7 +523,7 @@ describe access modes:
>  
>  Uppercase values for the specification letters are allowed as well.
>  Access mode specifications can be in any order. Examples of acceptable rules
> -are:
> +are::
>  
>  	TopSecret Secret  rx
>  	Secret    Unclass R
> @@ -456,7 +533,7 @@ are:
>  	New       Old     rRrRr
>  	Closed    Off     -
>  
> -Examples of unacceptable rules are:
> +Examples of unacceptable rules are::
>  
>  	Top Secret Secret     rx
>  	Ace        Ace        r
> @@ -469,6 +546,7 @@ access specifications. The dash is a placeholder, so "a-r" is the same
>  as "ar". A lone dash is used to specify that no access should be allowed.
>  
>  Applying Access Rules
> +~~~~~~~~~~~~~~~~~~~~~
>  
>  The developers of Linux rarely define new sorts of things, usually importing
>  schemes and concepts from other systems. Most often, the other systems are
> @@ -511,6 +589,7 @@ one process to another requires that the sender have write access to the
>  receiver. The receiver is not required to have read access to the sender.
>  
>  Setting Access Rules
> +~~~~~~~~~~~~~~~~~~~~
>  
>  The configuration file /etc/smack/accesses contains the rules to be set at
>  system startup. The contents are written to the special file
> @@ -520,6 +599,7 @@ one rule, with the most recently specified overriding any earlier
>  specification.
>  
>  Task Attribute
> +~~~~~~~~~~~~~~
>  
>  The Smack label of a process can be read from /proc/<pid>/attr/current. A
>  process can read its own Smack label from /proc/self/attr/current. A
> @@ -527,12 +607,14 @@ privileged process can change its own Smack label by writing to
>  /proc/self/attr/current but not the label of another process.
>  
>  File Attribute
> +~~~~~~~~~~~~~~
>  
>  The Smack label of a filesystem object is stored as an extended attribute
>  named SMACK64 on the file. This attribute is in the security namespace. It can
>  only be changed by a process with privilege.
>  
>  Privilege
> +~~~~~~~~~
>  
>  A process with CAP_MAC_OVERRIDE or CAP_MAC_ADMIN is privileged.
>  CAP_MAC_OVERRIDE allows the process access to objects it would
> @@ -540,6 +622,7 @@ be denied otherwise. CAP_MAC_ADMIN allows a process to change
>  Smack data, including rules and attributes.
>  
>  Smack Networking
> +~~~~~~~~~~~~~~~~
>  
>  As mentioned before, Smack enforces access control on network protocol
>  transmissions. Every packet sent by a Smack process is tagged with its Smack
> @@ -551,6 +634,7 @@ packet has write access to the receiving process and if that is not the case
>  the packet is dropped.
>  
>  CIPSO Configuration
> +~~~~~~~~~~~~~~~~~~~
>  
>  It is normally unnecessary to specify the CIPSO configuration. The default
>  values used by the system handle all internal cases. Smack will compose CIPSO
> @@ -571,13 +655,13 @@ discarded. The DOI is 3 by default. The value can be read from
>  The label and category set are mapped to a Smack label as defined in
>  /etc/smack/cipso.
>  
> -A Smack/CIPSO mapping has the form:
> +A Smack/CIPSO mapping has the form::
>  
>  	smack level [category [category]*]
>  
>  Smack does not expect the level or category sets to be related in any
>  particular way and does not assume or assign accesses based on them. Some
> -examples of mappings:
> +examples of mappings::
>  
>  	TopSecret 7
>  	TS:A,B    7 1 2
> @@ -597,25 +681,30 @@ value can be read from /sys/fs/smackfs/direct and changed by writing to
>  /sys/fs/smackfs/direct.
>  
>  Socket Attributes
> +~~~~~~~~~~~~~~~~~
>  
>  There are two attributes that are associated with sockets. These attributes
>  can only be set by privileged tasks, but any task can read them for their own
>  sockets.
>  
> -	SMACK64IPIN: The Smack label of the task object. A privileged
> +  SMACK64IPIN:
> +	The Smack label of the task object. A privileged
>  	program that will enforce policy may set this to the star label.
>  
> -	SMACK64IPOUT: The Smack label transmitted with outgoing packets.
> +  SMACK64IPOUT:
> +	The Smack label transmitted with outgoing packets.
>  	A privileged program may set this to match the label of another
>  	task with which it hopes to communicate.
>  
>  Smack Netlabel Exceptions
> +~~~~~~~~~~~~~~~~~~~~~~~~~
>  
>  You will often find that your labeled application has to talk to the outside,
>  unlabeled world. To do this there's a special file /sys/fs/smackfs/netlabel
> -where you can add some exceptions in the form of :
> -@IP1	   LABEL1 or
> -@.../MASK  LABEL2
> +where you can add some exceptions in the form of::
> +
> +	@IP1	   LABEL1 or
> +	@IP2/MASK  LABEL2
>  
>  It means that your application will have unlabeled access to @IP1 if it has
>  write access on LABEL1, and access to the subnet @IP2/MASK if it has write
> @@ -624,28 +713,32 @@ access on LABEL2.
>  Entries in the /sys/fs/smackfs/netlabel file are matched by longest mask
>  first, like in classless IPv4 routing.
>  
> -A special label '@' and an option '-CIPSO' can be used there :
> -@      means Internet, any application with any label has access to it
> --CIPSO means standard CIPSO networking
> +A special label '@' and an option '-CIPSO' can be used there::
>  
> -If you don't know what CIPSO is and don't plan to use it, you can just do :
> -echo 127.0.0.1 -CIPSO > /sys/fs/smackfs/netlabel
> -echo 0.0.0.0/0 @      > /sys/fs/smackfs/netlabel
> +	@      means Internet, any application with any label has access to it
> +	-CIPSO means standard CIPSO networking
> +
> +If you don't know what CIPSO is and don't plan to use it, you can just do::
> +
> +	echo 127.0.0.1 -CIPSO > /sys/fs/smackfs/netlabel
> +	echo 0.0.0.0/0 @      > /sys/fs/smackfs/netlabel
>  
>  If you use CIPSO on your 192.168.0.0/16 local network and need also unlabeled
> -Internet access, you can have :
> -echo 127.0.0.1      -CIPSO > /sys/fs/smackfs/netlabel
> -echo 192.168.0.0/16 -CIPSO > /sys/fs/smackfs/netlabel
> -echo 0.0.0.0/0      @      > /sys/fs/smackfs/netlabel
> +Internet access, you can have::
>  
> +	echo 127.0.0.1      -CIPSO > /sys/fs/smackfs/netlabel
> +	echo 192.168.0.0/16 -CIPSO > /sys/fs/smackfs/netlabel
> +	echo 0.0.0.0/0      @      > /sys/fs/smackfs/netlabel
>  
>  Writing Applications for Smack
> +------------------------------
>  
>  There are three sorts of applications that will run on a Smack system. How an
>  application interacts with Smack will determine what it will have to do to
>  work properly under Smack.
>  
>  Smack Ignorant Applications
> +---------------------------
>  
>  By far the majority of applications have no reason whatever to care about the
>  unique properties of Smack. Since invoking a program has no impact on the
> @@ -653,12 +746,14 @@ Smack label associated with the process the only concern likely to arise is
>  whether the process has execute access to the program.
>  
>  Smack Relevant Applications
> +---------------------------
>  
>  Some programs can be improved by teaching them about Smack, but do not make
>  any security decisions themselves. The utility ls(1) is one example of such a
>  program.
>  
>  Smack Enforcing Applications
> +----------------------------
>  
>  These are special programs that not only know about Smack, but participate in
>  the enforcement of system policy. In most cases these are the programs that
> @@ -666,15 +761,16 @@ set up user sessions. There are also network services that provide information
>  to processes running with various labels.
>  
>  File System Interfaces
> +----------------------
>  
>  Smack maintains labels on file system objects using extended attributes. The
>  Smack label of a file, directory, or other file system object can be obtained
> -using getxattr(2).
> +using getxattr(2)::
>  
>  	len = getxattr("/", "security.SMACK64", value, sizeof (value));
>  
>  will put the Smack label of the root directory into value. A privileged
> -process can set the Smack label of a file system object with setxattr(2).
> +process can set the Smack label of a file system object with setxattr(2)::
>  
>  	len = strlen("Rubble");
>  	rc = setxattr("/foo", "security.SMACK64", "Rubble", len, 0);
> @@ -683,17 +779,18 @@ will set the Smack label of /foo to "Rubble" if the program has appropriate
>  privilege.
>  
>  Socket Interfaces
> +-----------------
>  
>  The socket attributes can be read using fgetxattr(2).
>  
>  A privileged process can set the Smack label of outgoing packets with
> -fsetxattr(2).
> +fsetxattr(2)::
>  
>  	len = strlen("Rubble");
>  	rc = fsetxattr(fd, "security.SMACK64IPOUT", "Rubble", len, 0);
>  
>  will set the Smack label "Rubble" on packets going out from the socket if the
> -program has appropriate privilege.
> +program has appropriate privilege::
>  
>  	rc = fsetxattr(fd, "security.SMACK64IPIN, "*", strlen("*"), 0);
>  
> @@ -701,33 +798,40 @@ will set the Smack label "*" as the object label against which incoming
>  packets will be checked if the program has appropriate privilege.
>  
>  Administration
> +--------------
>  
>  Smack supports some mount options:
>  
> -	smackfsdef=label: specifies the label to give files that lack
> +  smackfsdef=label:
> +	specifies the label to give files that lack
>  	the Smack label extended attribute.
>  
> -	smackfsroot=label: specifies the label to assign the root of the
> +  smackfsroot=label:
> +	specifies the label to assign the root of the
>  	file system if it lacks the Smack extended attribute.
>  
> -	smackfshat=label: specifies a label that must have read access to
> +  smackfshat=label:
> +	specifies a label that must have read access to
>  	all labels set on the filesystem. Not yet enforced.
>  
> -	smackfsfloor=label: specifies a label to which all labels set on the
> +  smackfsfloor=label:
> +	specifies a label to which all labels set on the
>  	filesystem must have read access. Not yet enforced.
>  
>  These mount options apply to all file system types.
>  
>  Smack auditing
> +--------------
>  
>  If you want Smack auditing of security events, you need to set CONFIG_AUDIT
>  in your kernel configuration.
>  By default, all denied events will be audited. You can change this behavior by
> -writing a single character to the /sys/fs/smackfs/logging file :
> -0 : no logging
> -1 : log denied (default)
> -2 : log accepted
> -3 : log denied & accepted
> +writing a single character to the /sys/fs/smackfs/logging file::
> +
> +	0 : no logging
> +	1 : log denied (default)
> +	2 : log accepted
> +	3 : log denied & accepted
>  
>  Events are logged as 'key=value' pairs, for each event you at least will get
>  the subject, the object, the rights requested, the action, the kernel function
> @@ -735,6 +839,7 @@ that triggered the event, plus other pairs depending on the type of event
>  audited.
>  
>  Bringup Mode
> +------------
>  
>  Bringup mode provides logging features that can make application
>  configuration and system bringup easier. Configure the kernel with
> diff --git a/Documentation/admin-guide/LSM/index.rst b/Documentation/admin-guide/LSM/index.rst
> index 41f5262359f9..c980dfe9abf1 100644
> --- a/Documentation/admin-guide/LSM/index.rst
> +++ b/Documentation/admin-guide/LSM/index.rst
> @@ -36,5 +36,6 @@ the one "major" module (e.g. SELinux) if there is one configured.
>     apparmor
>     LoadPin
>     SELinux
> +   Smack
>     tomoyo
>     Yama
> diff --git a/Documentation/security/00-INDEX b/Documentation/security/00-INDEX
> index a55f781be0dd..cdb2294ec047 100644
> --- a/Documentation/security/00-INDEX
> +++ b/Documentation/security/00-INDEX
> @@ -1,7 +1,5 @@
>  00-INDEX
>  	- this file.
> -Smack.txt
> -	- documentation on the Smack Linux Security Module.
>  keys-ecryptfs.txt
>  	- description of the encryption keys for the ecryptfs filesystem.
>  keys-request-key.txt
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 3c1560c75aa6..3e78b5c9b3f9 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -11876,7 +11876,7 @@ L:	linux-security-module@...r.kernel.org
>  W:	http://schaufler-ca.com
>  T:	git git://github.com/cschaufler/smack-next
>  S:	Maintained
> -F:	Documentation/security/Smack.txt
> +F:	Documentation/admin-guide/LSM/Smack.rst
>  F:	security/smack/
>  
>  DRIVERS FOR ADAPTIVE VOLTAGE SCALING (AVS)

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