Novell AppArmor (2.0.1) Quick Start

This document helps you understand the main concepts behind Novell® AppArmor—the content of AppArmor profiles. Learn how to create or modify AppArmor profiles. You can create and manage AppArmor profile in three different ways. The most convenient interface to AppArmor is provided by means of the AppArmor YaST modules which can be used either in graphical or ncurses mode. The same functionality is provided by the AppArmor command line tools or if you just edit the profiles in a text editor.

1.0 AppArmor Modes

In complain or learning mode, violations of AppArmor profile rules, such as the profiled program accessing files not permitted by the profile, are detected. The violations are permitted, but also logged. This mode is convenient for developing profiles and is used by the AppArmor tools for generating profiles.

Manually activating complain mode (using the command line) adds a flag to the top of the profile so that /bin/foo becomes /bin/foo flags=(complain).

Loading a profile in enforcement mode enforces the policy defined in the profile as well as reports policy violation attempts to syslogd.

2.0 Starting and Stopping AppArmor

Use the rcapparmor command with one of the following parameters:

Load the kernel module, mount securityfs, parse and load profiles. Profiles and confinement are applied to any application started after this command was executed. Processes already running at the time AppArmor is started continue to run unconfined.
Unmount securityfs, and invalidate profiles.
Reload profiles.
If AppArmor is enabled, output how many profiles are loaded in complain or enforce mode.

Use the rcaaeventd command to control event logging with aa-eventd. Use the start and stop options to toggle the status of the aa-eventd and check its status using the status.

3.0 AppArmor Command Line Tools

Guess basic AppArmor profile requirements. autodep creates an approximate profile for the program or application examined. The resulting profile is called approximate because it does not necessarily contain all of the profile entries that the program needs to be confined properly.
Set an AppArmor profile to complain mode.
Set an AppArmor profile to enforce mode from complain mode.
Generate a profile. When running, you must specify a program to profile. If the specified program is not an absolute path, genprof searches the $PATH variable. If a profile does not exist, genprof creates one using autodep.
Manage AppArmor profiles. logprof is an interactive tool used to review the learning or complain mode output found in the AppArmor syslog entries and to generate new entries in AppArmor profiles.
Output a list of processes with tcp or udp ports that do not have AppArmor profiles loaded.

4.0 Methods of Profiling

Stand-Alone Profiling
Using genprof. Suitable for profiling small applications.
Systemic Profiling
Suitable for profiling large numbers of programs all at once and for profiling applications that may run forever.

To apply systemic profiling, proceed as follows:

  1. Create profiles for the individual programs that make up your application (autodep).
  2. Put relevant profiles into learning or complain mode.
  3. Exercise your application.
  4. Analyze the log (logprof).
  5. Repeat Steps 3-4.
  6. Edit the profiles.
  7. Return to enforce mode.
  8. Rescan all profiles (rcapparmor restart).

5.0 Learning Mode

When using genprof, logprof, or YaST in learning mode, you get several options for how to proceed:

Grant access.
Prevent access.
Modify the directory path to include all files in the suggested directory.
Glob w/Ext
Modify the original directory path while retaining the filename extension. This allows the program to access all files in the suggested directories that end with the specified extension.
Enable editing of the highlighted line. The new (edited) line appears at the bottom of the list. This option is called New in the logprof and genprof command line tools.
Abort logprof or YaST, losing all rule changes entered so far and leaving all profiles unmodified.
Close logprof or YaST, saving all rule changes entered so far and modifying all profiles.

6.0 Example Profile

# a variable definition
@{HOME} = /home/*/ /root/

# a comment about foo.
/usr/bin/foo {
  /bin/mount          ux,
  /dev/{,u}random     r,
  /etc/    r,
  /etc/foo.conf       r,
  /etc/foo/*          r,
  /lib/ld-*.so*       mr,
  /lib/lib*.so*       mr,
  /proc/[0-9]**       r,
  /usr/lib/**         mr,
  /tmp/        wr,
  /tmp/foo.*          lrw,
  /@{HOME}/.foo_file  rw,

  # a comment about foo's subprofile, bar.
  ^bar {
    /lib/ld-*.so*       mr,
    /usr/bin/bar        px,
    /var/spool/*        rwl,

7.0 Structure of a Profile

Profiles are simple text files in the /etc/apparmor.d directory. They consist of several parts: #include, capability entries, rules, and hats.

7.1 #include

This is the section of an AppArmor profile that refers to an include file, which mediates access permissions for programs. By using an include, you can give the program access to directory paths or files that are also required by other programs. Using includes can reduce the size of a profile. It is good practice to select includes when suggested.

To assist you in profiling your applications, AppArmor provides three classes of #includes: abstractions, program chunks, and variables.

Abstractions are #includes that are grouped by common application tasks. These tasks include access to authentication mechanisms, access to name service routines, common graphics requirements, and system accounting, for example, base, consoles, kerberosclient, perl, user-mail, user-tmp, authentication, bash, nameservice.

Program chunks are access controls for specific programs that a system administrator might want to control based on local site policy. Each chunk is used by a single program.

Using variables, you can design your profiles to be portable to different environments. Changes in the variable's content are just made in the variable definition while the profile containing the variable can remain untouched.

7.2 Capability Entries (POSIX.1e)

Capabilities statements are simply the word capability followed by the name of the POSIX.1e capability as defined in the capabilities(7) man page.

7.3 Rules: General Options for Files and Directories









7.4 Rules: Defining Execute Permissions

For executables that may be called from the confined programs, the profile creating tools ask you for an appropriate mode, which is also reflected directly in the profile itself:






Stay in the same (parent's) profile.



Requires that a separate profile exists for the executed program. No environment scrubbing.



Requires that a separate profile exists for the executed program. Uses environment scrubbing.



Executes the program without a profile. Avoid running programs in unconstrained or unconfined mode for security reasons. No environment scrubbing.



Executes the program without a profile. Avoid running programs in unconstrained or unconfined mode for security reasons. This mode makes use of environment scrubbing.

Allow Executable Mapping


allow PROT_EXEC with mmap(2) calls

WARNING: Running in ux Mode

Avoid running programs in ux mode as much as possible. A program running in ux mode is not only totally unprotected by AppArmor, but child processes inherit certain environment variables from the parent that might influence the child's execution behavior and create possible security risks.

For more information about the different file execute modes, refer to the apparmor.d(5) man page. For more information about setgid and setuid environment scrubbing, refer to the man page.

7.5 Rules: Paths and Globbing




Substitutes for any number of characters, except /.


Substitutes for any number of characters, including /.


Substitutes for any single character, except /.

[ abc ]

Substitutes for the single character a, b, or c.

[ a-c ]

Substitutes for the single character a, b, or c.

{ ab,cd }

Expand to one rule to match ab and another to match cd.

7.6 Hats

An AppArmor profile represents a security policy for an individual program instance or process. It applies to an executable program, but if a portion of the program needs different access permissions than other portions, the program can change hats to use a different security context, distinctive from the access of the main program. This is known as a hat or subprofile.

A profile can have an arbitrary number of subprofiles, but there are only two levels: a subprofile cannot have further sub-subprofiles.

The AppArmor ChangeHat feature can be used by applications to access hats or subprofiles during execution. Currently the packages apache2-mod_apparmor and tomcat_apparmor utilize ChangeHat to provide sub-process confinement for the Apache Web server and the Tomcat servlet container.

8.0 Helpful Additions

8.1 Autodocumentation

The tool sitar gathers all system configuration information available from your system and creates comprehensive system documentation. It can be used to document all new and changed profiles.

9.0 Logging and Auditing

All AppArmor events are logged using the system's audit interface (the auditd logging to /var/log/audit/audit.log). On top of this infrastructure, event notification can be configured. Configure this feature using YaST. It is based on severity levels according to /etc/apparmor/severity.db. Notification frequency and type of notification (such as e-mail) can be configured.

If auditd is not running, AppArmor logs to the system log located under /var/log/messages using the LOG_KERN facility.

Use YaST for generating reports in CSV or HTML format.

10.0 Directories and Files

Virtualized file representing the currently loaded set of profiles.
Location of AppArmor configuration files.
Location of profiles, named with the convention of replacing the / in pathnames with . (not for the root /) so profiles are easier to manage. For example, the profile for the program /usr/sbin/ntpd is named usr.sbin.ntpd.
Location of abstractions.
Location of program chunks.
Review the confinement status of a process and the profile that is used to confine the process. The ps auxZ command retrieves this information automatically.

11.0 For More Information

To learn more about the AppArmor project, check out the project's home page under Find more information on the concept and the configuration of AppArmor in the Novell AppArmor Administration Guide.