mod_apparmor - fine-grained AppArmor confinement for apache
An AppArmor profile applies to an executable program; if a portion of
the program needs different access permissions than other portions, the
program can "change hats" via change_hat(2) to a different role, also
known as a subprofile. The mod_apparmor apache module uses the
change_hat(2) mechanism to offer more fine-grained confinement of
dynamic elements within apache such as individual php and perl scripts,
while still allowing the performance benefits of using mod_php and
To use mod_apparmor with apache, ensure that mod_apparmor is configured
to be loaded into apache, either via yast or manual editing of the
httpd(8) configuration files, and restart apache. Make sure that
apparmor is also functioning.
Once mod_apparmor is loaded within apache, all requests to apache will
cause mod_apparmor to attempt to change into a hat named by the URI
(e.g. /app/some.cgi). If no such hat is found, it will fall back to
attempting to use the hat DEFAULT_URI; if that also does not exist, it
will fall back to using the global apache profile. Most static web
pages can simply make use of the DEFAULT_URI hat.
However, defining hats for every URI/URL would become tedious, so there
are a couple of configuration options that mod_apparmor supports:
AAHatName allows you to specify a hat to be used for a given apache
directory or location directive (see the apache documenation for
more details). Note that mod_apparmor behavior can become confused
if directory and location directives are intermingled; it's
preferred to stick to one type of directive. If the hat specified
by AAHatName does not exist in the apache profile, then it falls
back to the behavior above.
AADefaultHatName allows you to specify a default hat to be used for
vhosts and other apache server directives, so that you can have
different defaults for different virtual hosts. This can be
overridden by an AAHatName directive. If the AADefaultHatName hat
does not exist, it falls back to the behavior described above.
Additionally, before any requests come in to apache, mod_apparmor will
attempt to change hat into the HANDLING_UNTRUSTED_INPUT hat.
mod_apparmor will attempt to use this hat while apache is doing the
initial parsing of a given http request, before its given to a specific
handler (like mod_php) for processing.
mod_apparmor() currently only supports apache2, and has only been
tested with the prefork MPM configuration -- threaded configurations of
apache may not work correctly.
There are likely other bugs lurking about; if you find any, please
report them to bugzilla at <http://bugzilla.novell.com>.
apparmor(7), subdomain.conf(5), apparmor_parser(8), and