audit2why(1) — Linux manual page


AUDIT2ALLOW(1)                       NSA                      AUDIT2ALLOW(1)

NAME         top

       audit2allow - generate SELinux policy allow/dontaudit rules from logs
       of denied operations

       audit2why - translates SELinux audit messages into a  description  of
       why the access was denied (audit2allow -w)

SYNOPSIS         top

       audit2allow [options]

OPTIONS         top

       -a | --all
              Read input from audit and message log, conflicts with -i

       -b | --boot
              Read input from audit messages since last boot conflicts with

       -d | --dmesg
              Read input from output of /bin/dmesg.  Note that all audit
              messages are not available via dmesg when auditd is running;
              use "ausearch -m avc | audit2allow"  or "-a" instead.

       -D | --dontaudit
              Generate dontaudit rules (Default: allow)

       -h | --help
              Print a short usage message

       -i  <inputfile> | --input <inputfile>
              read input from <inputfile>

       -l | --lastreload
              read input only after last policy reload

       -m <modulename> | --module <modulename>
              Generate module/require output <modulename>

       -M <modulename>
              Generate loadable module package, conflicts with -o

       -p <policyfile> | --policy <policyfile>
              Policy file to use for analysis

       -o <outputfile> | --output <outputfile>
              append output to <outputfile>

       -r | --requires
              Generate require output syntax for loadable modules.

       -N | --noreference
              Do not generate reference policy, traditional style allow
              rules.  This is the default behavior.

       -R | --reference
              Generate reference policy using installed macros.  This
              attempts to match denials against interfaces and may be

       -x | --xperms
              Generate extended permission access vector rules

       -w | --why
              Translates SELinux audit messages into a description of why
              the access was denied

       -v | --verbose
              Turn on verbose output

DESCRIPTION         top

       This utility scans the logs for messages logged when the system
       denied permission for operations, and generates a snippet of policy
       rules which, if loaded into policy, might have allowed those
       operations to succeed. However, this utility only generates Type
       Enforcement (TE) allow rules.  Certain permission denials may require
       other kinds of policy changes, e.g. adding an attribute to a type
       declaration to satisfy an existing constraint, adding a role allow
       rule, or modifying a constraint.  The audit2why(8) utility may be
       used to diagnose the reason when it is unclear.

       Care must be exercised while acting on the output of this utility to
       ensure that the operations being permitted do not pose a security
       threat. Often it is better to define new domains and/or types, or
       make other structural changes to narrowly allow an optimal set of
       operations to succeed, as opposed to blindly implementing the
       sometimes broad changes recommended by this utility.   Certain
       permission denials are not fatal to the application, in which case it
       may be preferable to simply suppress logging of the denial via a
       'dontaudit' rule rather than an 'allow' rule.

EXAMPLE         top

       NOTE: These examples are for systems using the audit package. If you do
       not use the audit package, the AVC messages will be in /var/log/messages.
       Please substitute /var/log/messages for /var/log/audit/audit.log in the

       Using audit2allow to generate module policy

       $ cat /var/log/audit/audit.log | audit2allow -m local > local.te
       $ cat local.te
       module local 1.0;

       require {
               class file {  getattr open read };

               type myapp_t;
               type etc_t;

       allow myapp_t etc_t:file { getattr open read };
       <review local.te and customize as desired>

       Using audit2allow to generate module policy using reference policy

       $ cat /var/log/audit/audit.log | audit2allow -R -m local > local.te
       $ cat local.te
       policy_module(local, 1.0)

               type myapp_t;
               type etc_t;

       <review local.te and customize as desired>

       Building module policy using Makefile

       # SELinux provides a policy devel environment under
       # /usr/share/selinux/devel including all of the shipped
       # interface files.
       # You can create a te file and compile it by executing

       $ make -f /usr/share/selinux/devel/Makefile local.pp

       # This make command will compile a local.te file in the current
       # directory. If you did not specify a "pp" file, the make file
       # will compile all "te" files in the current directory.  After
       # you compile your te file into a "pp" file, you need to install
       # it using the semodule command.

       $ semodule -i local.pp

       Building module policy manually

       # Compile the module
       $ checkmodule -M -m -o local.mod local.te

       # Create the package
       $ semodule_package -o local.pp -m local.mod

       # Load the module into the kernel
       $ semodule -i local.pp

       Using audit2allow to generate and build module policy

       $ cat /var/log/audit/audit.log | audit2allow -M local
       Generating type enforcement file: local.te

       Compiling policy: checkmodule -M -m -o local.mod local.te
       Building package: semodule_package -o local.pp -m local.mod

       ******************** IMPORTANT ***********************

       In order to load this newly created policy package into the kernel,
       you are required to execute

       semodule -i local.pp

       Using audit2allow to generate monolithic (non-module) policy

       $ cd /etc/selinux/$SELINUXTYPE/src/policy
       $ cat /var/log/audit/audit.log | audit2allow >> domains/misc/local.te
       $ cat domains/misc/local.te
       allow cupsd_config_t unconfined_t:fifo_file { getattr ioctl };
       <review domains/misc/local.te and customize as desired>
       $ make load

AUTHOR         top

       This manual page was written by Manoj Srivastava
       <>, for the Debian GNU/Linux system. It was
       updated by Dan Walsh <>

       The audit2allow utility has contributions from several people,
       including Justin R. Smith and Yuichi Nakamura.  and Dan Walsh

COLOPHON         top

       This page is part of the selinux (Security-Enhanced Linux user-space
       libraries and tools) project.  Information about the project can be
       found at ⟨⟩.  If you
       have a bug report for this manual page, see
       ⟨⟩.  This
       page was obtained from the project's upstream Git repository
       ⟨⟩ on 2020-11-01.  (At that
       time, the date of the most recent commit that was found in the repos‐
       itory was 2020-10-31.)  If you discover any rendering problems in
       this HTML version of the page, or you believe there is a better or
       more up-to-date source for the page, or you have corrections or im‐
       provements to the information in this COLOPHON (which is not part of
       the original manual page), send a mail to

Security Enhanced Linux         October 2010                  AUDIT2ALLOW(1)