docs: convert extras doc md->rst

Type: improvement

Change-Id: Ie3b25a86b99098d2b3a21a11fc73234c8ed589d6
Signed-off-by: Nathan Skrzypczak <nathan.skrzypczak@gmail.com>

1 files changed, 554 insertions, 0 deletions

diff --git a/extras/selinux/selinux_doc.rst b/extras/selinux/selinux_doc.rst
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+.. _selinux_doc:
+
+SELinux - VPP Custom SELinux Policy
+===================================
+
+Overview
+--------
+
+Security-enhanced Linux (SELinux) is a security feature in the Linux
+kernel. At a very high level, SELinux implements mandatory access
+controls (MAC), as opposed to discretionary access control (DAC)
+implemented in standard Linux. MAC defines how processes can interact
+with other system components (Files, Directories, Other Processes,
+Pipes, Sockets, Network Ports). Each system component is assigned a
+label, and then the SELinux Policy defines which labels and which
+actions on each label a process is able to perform. The VPP Custom
+SELinux Policy defines the actions VPP is allowed to perform on which
+labels.
+
+The VPP Custom SELinux Policy is intended to be installed on RPM based
+platforms (tested on CentOS 7 and RHEL 7). Though SELinux can run on
+Debian platforms, it typically is not and therefore is not currently
+being built for Debian.
+
+The VPP Custom SELinux Policy does not enable or disable SELinux, only
+allows VPP to run when SELinux is enabled. A fresh install of either
+Fedora, CentOS or RHEL will have SELinux enabled by default. To
+determine if SELinux is enabled on a given system and enable it if
+needed, run:
+
+::
+
+      $ getenforce
+      Permissive
+
+      $ sudo setenforce 1
+
+      $ getenforce
+      Enforcing
+
+To make the change persistent, modify the following file to set
+``SELINUX=enforcing``:
+
+::
+
+      $ sudo vi /etc/selinux/config
+      :
+      # This file controls the state of SELinux on the system.
+      # SELINUX= can take one of these three values:
+      #     enforcing - SELinux security policy is enforced.
+      #     permissive - SELinux prints warnings instead of enforcing.
+      #     disabled - No SELinux policy is loaded.
+      SELINUX=enforcing
+      :
+
+Installation
+------------
+
+To install VPP, see the installation instructions on the VPP Wiki
+(https://wiki.fd.io/view/VPP/Installing_VPP_binaries_from_packages). The
+VPP Custom SELinux Policy is packaged in its own RPM starting in 18.04,
+``vpp-selinux-policy-<VERSION>-<RELEASE>.rpm``. It is packaged and
+installed along with the other VPP RPMs.
+
+Fresh Install of VPP
+~~~~~~~~~~~~~~~~~~~~
+
+If VPP has never been installed on a system, then starting in 18.04, the
+VPP Custom SELinux Policy will be installed with the other RPMs and all
+the system components managed by VPP will be labeled properly.
+
+Fix SELinux Labels for VPP
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+In the case where the VPP Custom Policy is being installed for the first
+time, either because VPP has been upgraded or packages were removed and
+then reinstalled, several directories and files will not not be properly
+labeled. The labels on these files will need to be fixed for VPP to run
+properly with SELinux enabled. After the VPP Custom SELinux Policy is
+installed, run the following commands to fix the labels. If VPP is
+already running, make sure to restart VPP after the labels are fixed.
+This change is persistent for the life of the file. Once the VPP Custom
+Policy is installed on the system, subsequent files created by VPP will
+be labeled properly. This is only to fix files created by VPP prior to
+the VPP Custom Policy being installed.
+
+::
+
+     $ sudo restorecon -Rv /etc/vpp/
+     $ sudo restorecon -Rv /usr/lib/vpp_api_test_plugins/
+     $ sudo restorecon -Rv /usr/lib/vpp_plugins/
+     $ sudo restorecon -Rv /usr/share/vpp/
+     $ sudo restorecon -Rv /var/run/vpp/
+
+     $ sudo chcon -t vpp_tmp_t /tmp/vpp_*
+     $ sudo chcon -t vpp_var_run_t /var/run/.vpp_*
+
+**NOTE:** Because the VPP APIs allow custom filenames in certain
+scenarios, the above commands may not handle all files. Inspect your
+system and correct any files that are mislabeled. For example, to verify
+all VPP files in ``/tmp/`` are labeled properly, run:
+
+::
+
+     $ sudo ls -alZ /tmp/
+
+Any files not properly labeled with ``vpp_tmp_t``, run:
+
+::
+
+     $ sudo chcon -t vpp_tmp_t /tmp/<filename>
+
+VPP Files
+---------
+
+Recommended Default File Directories
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Documentation in the VPP Wiki (https://wiki.fd.io/view/VPP/) and doxygen
+generated documentation have examples with files located in certain
+directories. Some of the recommend file locations have been moved to
+satisfy SELinux. Most of the documentation has been updated, but links
+to older documentation still exist and there may have been instances
+that were missed. Use the file locations described below to allow
+SELinux to properly label the given files.
+
+File locations that have changed: \* VPP Debug CLI Script Files \* vHost
+Sockets \* VPP Log Files
+
+VPP Debug CLI Script Files
+^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The VPP Debug CLI, ``vppctl``, allows a sequence of CLI commands to be
+read from a file and executed. To avoid from having to grant VPP access
+to all of ``/tmp/`` and possibly ``/home/`` sub-directories, it is
+recommended that any VPP Debug CLI script files be placed in a common
+directory such as ``/usr/share/vpp/``.
+
+For example:
+
+::
+
+   $ cat /usr/share/vpp/scripts/gigup.txt
+   set interface state GigabitEthernet0/8/0 up
+   set interface state GigabitEthernet0/9/0 up
+
+To execute:
+
+::
+
+   $ vppctl exec /usr/share/vpp/scripts/gigup.txt
+
+Or
+
+::
+
+   $ vppctl
+       _______    _        _   _____  ___
+    __/ __/ _ \  (_)__    | | / / _ \/ _ \
+    _/ _// // / / / _ \   | |/ / ___/ ___/
+    /_/ /____(_)_/\___/   |___/_/  /_/
+
+   vpp# exec /usr/share/vpp/scripts/gigup.txt
+   vpp# quit
+
+If the file is not labeled properly, you will see something similar to:
+
+::
+
+   $ vppctl exec /home/<user>/dev/vpp/scripts/vppctl/gigup.txt
+   exec: failed to open `/home/<user>/dev/vpp/scripts/vppctl/gigup.txt': Permission denied
+
+   $ ls -alZ
+   drwxrwxr-x. <user> <user> unconfined_u:object_r:user_home_t:s0 .
+   drwxrwxr-x. <user> <user> unconfined_u:object_r:user_home_t:s0 ..
+   -rw-r--r--. <user> <user> unconfined_u:object_r:user_home_t:s0 gigup.txt
+
+Original Documentation
+''''''''''''''''''''''
+
+Some of the original documentation showed script files being executed
+out of ``/tmp/``. Convenience also may lead to script files being placed
+in ``/home/<user>/`` subdirectories. If a file is generated by the VPP
+process in ``/tmp/``, for example a trace file or pcap file, it will get
+properly labeled with the SELinux label ``vpp_tmp_t``. When a file is
+created, unless a rule is in place for the process that created it, the
+file will inherit the SELinux label of the parent directory. So if a
+user creates a file themselves in ``/tmp/``, it will get the SELinux
+label ``tmp_t``, which VPP does not have permission to access. Therefore
+it is recommended that script files are located as described above.
+
+vHost Sockets
+^^^^^^^^^^^^^
+
+vHost sockets are created from VPP perspective in either Server or
+Client mode. In Server mode, the socket name is provided to VPP and VPP
+creates the socket. In Client mode, the socket name is provided to VPP
+and the hypervisor creates the socket. In order for VPP and hypervisor
+to share the socket resource with SELinux enabled, a rule in the VPP
+Custom SELinux Policy has been added. This rules allows processes with
+the ``svirt_t`` label (the hypervisor) to access sockets with the
+``vpp_var_run_t`` label. As such, when SELinux is enabled, vHost sockets
+should be created in the directory ``/var/run/vpp/``.
+
+.. _original-documentation-1:
+
+Original Documentation
+''''''''''''''''''''''
+
+Some of the original documentation showed vHost sockets being created in
+the directory ``/tmp/``. To work properly with SELinux enabled, vHost
+sockets should be created as described above.
+
+VPP Log Files
+^^^^^^^^^^^^^
+
+The VPP log file location is set by updating the
+``/etc/vpp/startup.conf`` file:
+
+::
+
+   vi /etc/vpp/startup.conf
+   unix {
+   :
+     log /var/log/vpp/vpp.log
+   :
+   }
+
+By moving the log file to ``/var/log/vpp/``, it will get the label
+``vpp_log_t``, which indicates that the files are log files so they
+benefit from the associated rules (for example granting rights to
+logrotate so that it can manipulate them).
+
+.. _original-documentation-2:
+
+Original Documentation
+''''''''''''''''''''''
+
+The default ``startup.conf`` file creates the VPP log file in
+``/tmp/vpp.log``. By leaving the log file in ``/tmp/``, it will get the
+label ``vpp_tmp_t``. Moving it to ``/var/log/vpp/``, it will get the
+label ``vpp_log_t``.
+
+Use of Non-default File Directories
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+VPP installs multiple files on the system. Some files have fixed
+directory and file names: - /etc/bash_completion.d/vppctl_completion -
+/etc/sysctl.d/80-vpp.conf - /usr/lib/systemd/system/vpp.service
+
+Others files have default directory and file names but the default can
+be overwritten: - /etc/vpp/startup.conf - Can be changed via the
+``/usr/lib/systemd/system/vpp.service`` file by changing the -c option
+on the VPP command line:
+
+::
+
+   ExecStart=/usr/bin/vpp -c /etc/vpp/startup.conf
+
+-  /run/vpp/cli.sock
+
+   -  Can be changed via the ``/etc/vpp/startup.conf`` file by changing
+      the cli-listen setting:
+
+::
+
+   unix {
+   :
+     cli-listen /run/vpp/cli.sock
+   :
+   }
+
+-  /var/log/vpp/vpp.log
+
+   -  Can be changed via the ``/etc/vpp/startup.conf`` file by changing
+      the log setting:
+
+::
+
+   unix {
+     :
+     log /var/log/vpp/vpp.log
+     :
+   }
+
+If the directory of any VPP installed files is changed from the default,
+ensure that the proper SELiunx label is applied. The SELinux label can
+be determined by passing the -Z option to many common Linux commands:
+
+::
+
+   ls -alZ /run/vpp/
+   drwxr-xr-x. root vpp  system_u:object_r:vpp_var_run_t:s0 .
+   drwxr-xr-x. root root system_u:object_r:var_run_t:s0     ..
+   srwxrwxr-x. root vpp  system_u:object_r:vpp_var_run_t:s0 cli.sock
+
+VPP SELinux Types
+~~~~~~~~~~~~~~~~~
+
+The following SELinux types are created by the VPP Custom SELinux
+Policy: - ``vpp_t`` - Applied to: - VPP process and spawned threads.
+
+-  ``vpp_config_rw_t`` - Applied to:
+
+   -  ``/etc/vpp/*``
+
+-  ``vpp_tmp_t`` - Applied to:
+
+   -  ``/tmp/*``
+
+-  ``vpp_exec_t`` - Applied to:
+
+   -  ``/usr/bin/*``
+
+-  ``vpp_lib_t`` - Applied to:
+
+   -  ``/usr/lib/vpp_api_test_plugins/*``
+   -  ``/usr/lib/vpp_plugins/*``
+
+-  ``vpp_unit_file_t`` - Applied to:
+
+   -  ``/usr/lib/systemd/system/vpp.*``
+
+-  ``vpp_log_t`` - Applied to:
+
+   -  ``/var/log/vpp/*``
+
+-  ``vpp_var_run_t`` - Applied to:
+
+   -  ``/var/run/vpp/*``
+
+Debug SELinux Issues
+--------------------
+
+If SELinux issues are suspected, there are a few steps that can be taken
+to debug the issue. This section provides a few pointers on on those
+steps. Any SELinux JIRAs will need this information to properly address
+the issue.
+
+Additional SELinux Packages and Setup
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+First, install the SELinux troubleshooting packages:
+
+::
+
+   $ sudo yum -y install setroubleshoot setroubleshoot-server setools-console
+   -- OR --
+   $ sudo dnf -y install setroubleshoot setroubleshoot-server setools-console
+
+To enable proper logging, restart auditd:
+
+::
+
+   $ sudo service auditd restart
+
+While debugging issues, it is best to set SELinux to ``Permissive``
+mode. In ``Permissive`` mode, SELinux will still detect and flag errors,
+but will allow processes to continue normal operation. This allows
+multiple errors to be collected at once as opposed to breaking on each
+individual error. To set SELinux to ``Permissive`` mode (until next
+reboot or it is set back), use:
+
+::
+
+   $ sudo setenforce 0
+
+   $ getenforce
+   Permissive
+
+After debugging, to set SELinux back to ``Enforcing`` mode, use:
+
+::
+
+   $ sudo setenforce 1
+
+   $ getenforce
+   Enforcing
+
+Debugging
+~~~~~~~~~
+
+Once the SELinux troubleshooting packages are installed, perform the
+actions that are suspected to be blocked by SELinux. Either ``tail`` the
+log during these actions or ``grep`` the log for additional SELinux
+logs:
+
+::
+
+   sudo tail -f /var/log/messages
+   -- OR --
+   sudo journalctl -f
+
+Below are some examples of SELinux logs that are generated:
+
+::
+
+   May 14 11:28:34 svr-22 setroubleshoot: SELinux is preventing /usr/bin/vpp from read access on the file hostCreate.txt. For complete SELinux messages run: sealert -l a418f869-f470-4c8a-b8e9-bdd41f2dd60b
+   May 14 11:28:34 svr-22 python: SELinux is preventing /usr/bin/vpp from read access on the file hostCreate.txt.#012#012*****  Plugin catchall (100. confidence) suggests   **************************#012#012If you believe that vpp should be allowed read access on the hostCreate.txt file by default.#012Then you should report this as a bug.#012You can generate a local policy module to allow this access.#012Do#012allow this access for now by executing:#012# ausearch -c 'vpp_main' --raw | audit2allow -M my-vppmain#012# semodule -i my-vppmain.pp#012
+   May 14 11:28:34 svr-22 setroubleshoot: SELinux is preventing /usr/bin/vpp from read access on the file hostCreate.txt. For complete SELinux messages run: sealert -l a418f869-f470-4c8a-b8e9-bdd41f2dd60b
+   May 14 11:28:34 svr-22 python: SELinux is preventing /usr/bin/vpp from read access on the file hostCreate.txt.#012#012*****  Plugin catchall (100. confidence) suggests   **************************#012#012If you believe that vpp should be allowed read access on the hostCreate.txt file by default.#012Then you should report this as a bug.#012You can generate a local policy module to allow this access.#012Do#012allow this access for now by executing:#012# ausearch -c 'vpp_main' --raw | audit2allow -M my-vppmain#012# semodule -i my-vppmain.pp#012
+   May 14 11:28:37 svr-22 setroubleshoot: SELinux is preventing vpp_main from map access on the packet_socket packet_socket. For complete SELinux messages run: sealert -l ab6667d9-3f14-4dbd-96a0-7a655f7b4eb1
+   May 14 11:28:37 svr-22 python: SELinux is preventing vpp_main from map access on the packet_socket packet_socket.#012#012*****  Plugin catchall (100. confidence) suggests   **************************#012#012If you believe that vpp_main should be allowed map access on the packet_socket packet_socket by default.#012Then you should report this as a bug.#012You can generate a local policy module to allow this access.#012Do#012allow this access for now by executing:#012# ausearch -c 'vpp_main' --raw | audit2allow -M my-vppmain#012# semodule -i my-vppmain.pp#012
+   May 14 11:28:51 svr-22 setroubleshoot: SELinux is preventing vpp_main from map access on the packet_socket packet_socket. For complete SELinux messages run: sealert -l ab6667d9-3f14-4dbd-96a0-7a655f7b4eb1
+   May 14 11:28:51 svr-22 python: SELinux is preventing vpp_main from map access on the packet_socket packet_socket.#012#012*****  Plugin catchall (100. confidence) suggests   **************************#012#012If you believe that vpp_main should be allowed map access on the packet_socket packet_socket by default.#012Then you should report this as a bug.#012You can generate a local policy module to allow this access.#012Do#012allow this access for now by executing:#012# ausearch -c 'vpp_main' --raw | audit2allow -M my-vppmain#012# semodule -i my-vppmain.pp#012
+
+From the logs above, there are two sets of commands that are recommended
+to be run. The first is to run the ``sealert`` command. The second is to
+run the ``ausearch | audit2allow`` commands and the ``semodule``
+command.
+
+sealert Command
+^^^^^^^^^^^^^^^
+
+This ``sealert`` command provides a more detailed output for the given
+issue detected.
+
+::
+
+   $ sealert -l a418f869-f470-4c8a-b8e9-bdd41f2dd60b
+   SELinux is preventing /usr/bin/vpp from 'read, write' accesses on the chr_file noiommu-0.
+
+   *****  Plugin device (91.4 confidence) suggests   ****************************
+
+   If you want to allow vpp to have read write access on the noiommu-0 chr_file
+   Then you need to change the label on noiommu-0 to a type of a similar device.
+   Do
+   # semanage fcontext -a -t SIMILAR_TYPE 'noiommu-0'
+   # restorecon -v 'noiommu-0'
+
+   *****  Plugin catchall (9.59 confidence) suggests   **************************
+
+   If you believe that vpp should be allowed read write access on the noiommu-0 chr_file by default.
+   Then you should report this as a bug.
+   You can generate a local policy module to allow this access.
+   Do
+   allow this access for now by executing:
+   # ausearch -c 'vpp' --raw | audit2allow -M my-vpp
+   # semodule -i my-vpp.pp
+
+
+   Additional Information:
+   Source Context                system_u:system_r:vpp_t:s0
+   Target Context                system_u:object_r:device_t:s0
+   Target Objects                noiommu-0 [ chr_file ]
+   Source                        vpp
+   Source Path                   /usr/bin/vpp
+   Port                          <Unknown>
+   Host                          vpp_centos7_selinux
+   Source RPM Packages           vpp-19.01.2-rc0~17_gcfd3086.x86_64
+   Target RPM Packages
+   Policy RPM                    selinux-policy-3.13.1-229.el7_6.12.noarch
+   Selinux Enabled               True
+   Policy Type                   targeted
+   Enforcing Mode                Permissive
+   Host Name                     vpp_centos7_selinux
+   Platform                      Linux vpp_centos7_selinux
+                                 3.10.0-957.12.1.el7.x86_64 #1 SMP Mon Apr 29
+                                 14:59:59 UTC 2019 x86_64 x86_64
+   Alert Count                   1
+   First Seen                    2019-05-13 18:10:50 EDT
+   Last Seen                     2019-05-13 18:10:50 EDT
+   Local ID                      a418f869-f470-4c8a-b8e9-bdd41f2dd60b
+
+   Raw Audit Messages
+   type=AVC msg=audit(1557785450.964:257): avc:  denied  { read write } for  pid=5273 comm="vpp" name="noiommu-0" dev="devtmpfs" ino=36022 scontext=system_u:system_r:vpp_t:s0 tcontext=system_u:object_r:device_t:s0 tclass=chr_file permissive=1
+
+
+   type=AVC msg=audit(1557785450.964:257): avc:  denied  { open } for  pid=5273 comm="vpp" path="/dev/vfio/noiommu-0" dev="devtmpfs" ino=36022 scontext=system_u:system_r:vpp_t:s0 tcontext=system_u:object_r:device_t:s0 tclass=chr_file permissive=1
+
+
+   type=SYSCALL msg=audit(1557785450.964:257): arch=x86_64 syscall=open success=yes exit=ENOTBLK a0=7fb395ffd7f0 a1=2 a2=7fb395ffd803 a3=7fb395ffe2a0 items=0 ppid=1 pid=5273 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=993 sgid=0 fsgid=993 tty=(none) ses=4294967295 comm=vpp exe=/usr/bin/vpp subj=system_u:system_r:vpp_t:s0 key=(null)
+
+   Hash: vpp,vpp_t,device_t,chr_file,read,write
+
+In general, this command pumps out too much info and is only needed for
+additional debugging for tougher issues. Also note that once the process
+being tested is restarted, this command loses it’s context and will not
+provide any information:
+
+::
+
+   $ sealert -l a418f869-f470-4c8a-b8e9-bdd41f2dd60b
+   Error
+   query_alerts error (1003): id (a418f869-f470-4c8a-b8e9-bdd41f2dd60b) not found
+
+ausearch \| audit2allow and semodule Commands
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+These set of commands are more useful for basic debugging. The
+``ausearch | audit2allow`` commands generate a set files. It may be
+worthwhile to run the commands in a temporary subdirectory:
+
+::
+
+   $ mkdir test-01/; cd test-01/
+
+   $ sudo ausearch -c 'vpp_main' --raw | audit2allow -M my-vppmain
+
+   $ ls
+   my-vpp.pp  my-vpp.te
+
+   $ cat my-vpp.te
+   module my-vpp 1.0;
+
+   require {
+           type user_home_t;
+           type vpp_t;
+           class packet_socket map;
+           class file { open read };
+   }
+
+   #============= vpp_t ==============
+   allow vpp_t self:packet_socket map;
+   allow vpp_t user_home_t:file { open read };
+
+As shown above, the file ``my-vpp.te`` has been generated. This file
+shows possible changes to the SELinux policy that may fix the issue. If
+an SELinux policy was being created from scratch, this policy could be
+applied using the ``semodule -i my-vpp.pp`` command. HOWEVER, VPP
+already has a policy in place. So these changes need to be incorporated
+into the existing policy. The VPP SELinux policy is located in the
+following files:
+
+::
+
+   $ ls extras/selinux/
+   selinux_doc.md  vpp-custom.fc  vpp-custom.if  vpp-custom.te
+
+In this example, ``map`` needs to be added to the ``packet_socket``
+class. If the ``vpp-custom.te`` is examined (prior to this fix), then
+one would see that the ``packet_socket`` class is already defined and
+just needs to be updated:
+
+::
+
+   $ vi extras/selinux/vpp-custom.te
+   :
+   allow vpp_t self:process { execmem execstack setsched signal }; # too benevolent
+   allow vpp_t self:packet_socket { bind create setopt ioctl };  <---
+   allow vpp_t self:tun_socket { create relabelto relabelfrom };
+   :
+
+Before blindly applying the changes proposed by the
+``ausearch | audit2allow`` commands, try to determine what is being
+allowed by the policy and determine if this is desired, or if the code
+can be reworked to no longer require the suggested permission. In the
+``my-vpp.te`` file from above, it is suggested to allow ``vpp_t``
+(i.e. the VPP process) access to all files in the home directory
+(``allow vpp_t user_home_t:file { open read };``). This was because a
+``vppctl exec`` command was executed calling a script located in the
+``/home/<user>/`` directory. Once this script was run from the
+``/usr/share/vpp/`` directory as described in a section above, these
+permissions were no longer needed.