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42b4a44b74
Add support for extended permissions to audit2allow. Extend AuditParser
to parse the 'ioctlcmd' field in AVC message. Extend PolicyGenerator to
generate allowxperm rules. Add the '-x'/'--xperms' option to audit2allow
to turn on generating of extended permission AV rules.
AVCMessage parses the ioctlcmd field in AVC messages. AuditParser
converts the ioctlcmd values into generic representation of extended
permissions that is stored in access vectors.
Extended permissions are represented by operations (currently only
'ioctl') and values associated to the operations. Values (for example
'~{ 0x42 1234 23-34 }') are stored in the XpermSet class.
PolicyGenerator contains new method to turn on generating of xperms.
When turned on, for each access vector, standard AV rule and possibly
several xperm AV rules are generated. Xperm AV rules are represented by
the AVExtRule class.
With xperm generating turned off, PolicyGenerator provides comments
about extended permissions in certain situations. When the AVC message
contains the ioctlcmd field and the access would be allowed according to
the policy, PolicyGenerator warns about xperm rules being the possible
cause of the denial.
Signed-off-by: Jan Zarsky <jzarsky@redhat.com>
227 lines
7.0 KiB
Groff
227 lines
7.0 KiB
Groff
.\" Hey, Emacs! This is an -*- nroff -*- source file.
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.\" Copyright (c) 2005 Manoj Srivastava <srivasta@debian.org>
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.\" Copyright (c) 2010 Dan Walsh <dwalsh@redhat.com>
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.\"
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.\" This is free documentation; you can redistribute it and/or
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.\" modify it under the terms of the GNU General Public License as
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.\" published by the Free Software Foundation; either version 2 of
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.\" the License, or (at your option) any later version.
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.\"
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.\" The GNU General Public License's references to "object code"
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.\" and "executables" are to be interpreted as the output of any
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.\" document formatting or typesetting system, including
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.\" intermediate and printed output.
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.\"
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.\" This manual is distributed in the hope that it will be useful,
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.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
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.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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.\" GNU General Public License for more details.
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.\"
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.\" You should have received a copy of the GNU General Public
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.\" License along with this manual; if not, write to the Free
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.\" Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139,
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.\" USA.
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.\"
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.\"
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.TH AUDIT2ALLOW "1" "October 2010" "Security Enhanced Linux" NSA
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.SH NAME
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.BR audit2allow
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\- generate SELinux policy allow/dontaudit rules from logs of denied operations
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.BR audit2why
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\- translates SELinux audit messages into a description of why the access was denied (audit2allow \-w)
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.SH SYNOPSIS
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.B audit2allow
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.RI [ options "] "
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.SH OPTIONS
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.TP
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.B "\-a" | "\-\-all"
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Read input from audit and message log, conflicts with \-i
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.TP
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.B "\-b" | "\-\-boot"
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Read input from audit messages since last boot conflicts with \-i
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.TP
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.B "\-d" | "\-\-dmesg"
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Read input from output of
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.I /bin/dmesg.
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Note that all audit messages are not available via dmesg when
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auditd is running; use "ausearch \-m avc | audit2allow" or "\-a" instead.
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.TP
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.B "\-D" | "\-\-dontaudit"
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Generate dontaudit rules (Default: allow)
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.TP
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.B "\-h" | "\-\-help"
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Print a short usage message
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.TP
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.B "\-i <inputfile>" | "\-\-input <inputfile>"
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read input from
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.I <inputfile>
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.TP
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.B "\-l" | "\-\-lastreload"
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read input only after last policy reload
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.TP
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.B "\-m <modulename>" | "\-\-module <modulename>"
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Generate module/require output <modulename>
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.TP
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.B "\-M <modulename>"
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Generate loadable module package, conflicts with \-o
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.TP
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.B "\-p <policyfile>" | "\-\-policy <policyfile>"
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Policy file to use for analysis
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.TP
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.B "\-o <outputfile>" | "\-\-output <outputfile>"
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append output to
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.I <outputfile>
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.TP
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.B "\-r" | "\-\-requires"
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Generate require output syntax for loadable modules.
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.TP
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.B "\-N" | "\-\-noreference"
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Do not generate reference policy, traditional style allow rules.
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This is the default behavior.
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.TP
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.B "\-R" | "\-\-reference"
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Generate reference policy using installed macros.
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This attempts to match denials against interfaces and may be inaccurate.
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.TP
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.B "\-x" | "\-\-xperms"
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Generate extended permission access vector rules
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.TP
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.B "\-w" | "\-\-why"
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Translates SELinux audit messages into a description of why the access was denied
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.TP
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.B "\-v" | "\-\-verbose"
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Turn on verbose output
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.SH DESCRIPTION
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.PP
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This utility scans the logs for messages logged when the system denied
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permission for operations, and generates a snippet of policy rules
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which, if loaded into policy, might have allowed those operations to
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succeed. However, this utility only generates Type Enforcement (TE) allow
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rules. Certain permission denials may require other kinds of policy changes,
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e.g. adding an attribute to a type declaration to satisfy an existing
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constraint, adding a role allow rule, or modifying a constraint. The
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.BR audit2why (8)
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utility may be used to diagnose the reason when it is unclear.
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.PP
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Care must be exercised while acting on the output of this utility to
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ensure that the operations being permitted do not pose a security
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threat. Often it is better to define new domains and/or types, or make other
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structural changes to narrowly allow an optimal set of operations to
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succeed, as opposed to blindly implementing the sometimes broad
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changes recommended by this utility. Certain permission denials are
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not fatal to the application, in which case it may be preferable to
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simply suppress logging of the denial via a 'dontaudit' rule rather than
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an 'allow' rule.
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.PP
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.SH EXAMPLE
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.nf
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.B NOTE: These examples are for systems using the audit package. If you do
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.B not use the audit package, the AVC messages will be in /var/log/messages.
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.B Please substitute /var/log/messages for /var/log/audit/audit.log in the
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.B examples.
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.PP
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.B Using audit2allow to generate module policy
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$ cat /var/log/audit/audit.log | audit2allow \-m local > local.te
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$ cat local.te
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module local 1.0;
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require {
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class file { getattr open read };
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type myapp_t;
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type etc_t;
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};
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allow myapp_t etc_t:file { getattr open read };
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<review local.te and customize as desired>
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.B Using audit2allow to generate module policy using reference policy
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$ cat /var/log/audit/audit.log | audit2allow \-R \-m local > local.te
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$ cat local.te
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policy_module(local, 1.0)
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gen_require(`
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type myapp_t;
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type etc_t;
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};
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files_read_etc_files(myapp_t)
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<review local.te and customize as desired>
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.B Building module policy using Makefile
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# SELinux provides a policy devel environment under
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# /usr/share/selinux/devel including all of the shipped
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# interface files.
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# You can create a te file and compile it by executing
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$ make \-f /usr/share/selinux/devel/Makefile local.pp
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# This make command will compile a local.te file in the current
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# directory. If you did not specify a "pp" file, the make file
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# will compile all "te" files in the current directory. After
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# you compile your te file into a "pp" file, you need to install
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# it using the semodule command.
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$ semodule \-i local.pp
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.B Building module policy manually
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# Compile the module
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$ checkmodule \-M \-m \-o local.mod local.te
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# Create the package
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$ semodule_package \-o local.pp \-m local.mod
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# Load the module into the kernel
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$ semodule \-i local.pp
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.B Using audit2allow to generate and build module policy
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$ cat /var/log/audit/audit.log | audit2allow \-M local
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Generating type enforcement file: local.te
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Compiling policy: checkmodule \-M \-m \-o local.mod local.te
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Building package: semodule_package \-o local.pp \-m local.mod
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******************** IMPORTANT ***********************
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In order to load this newly created policy package into the kernel,
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you are required to execute
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semodule \-i local.pp
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.B Using audit2allow to generate monolithic (non\-module) policy
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$ cd /etc/selinux/$SELINUXTYPE/src/policy
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$ cat /var/log/audit/audit.log | audit2allow >> domains/misc/local.te
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$ cat domains/misc/local.te
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allow cupsd_config_t unconfined_t:fifo_file { getattr ioctl };
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<review domains/misc/local.te and customize as desired>
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$ make load
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.fi
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.PP
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.SH AUTHOR
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This manual page was written by
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.I Manoj Srivastava <srivasta@debian.org>,
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for the Debian GNU/Linux system. It was updated by Dan Walsh <dwalsh@redhat.com>
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.PP
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The
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.B audit2allow
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utility has contributions from several people, including
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.I Justin R. Smith
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and
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.I Yuichi Nakamura.
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and
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.I Dan Walsh
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