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In testing against the 4.1 kernel, the syscall_sysctl testcase started failing even in the unconfined case. What the test program does is attempt to adjust the kernel.threads-max sysctl to be slightly larger and see if the operation succeeds by reading the value back out. It also attempts to save the original value and restore it. The test was failing because (in VMs at least) the default value chosen by the kernel for the kernel.threads-max setting was high enough that attempts to increase it would be ignored (likely to prevent too much use of kernel memory by threads), helpfully without any message being report to dmesg. Thus, the initial read of the current value would succeed, the write of that value + 1024 would appear to succeed, but then reading the value back out and comparing it to the expected value would fail, as it would still be the original value, not the expected new value. This patch attempts to address this by first attempting to raise the value, and if that does not appear to work, to then attempt to lower it. It also refactors the code a bit by creating helper functions to perform the actual sysctl(2) calls to make the code a bit easier to read. Signed-off-by: Steve Beattie <steve@nxnw.org> Acked-by: Seth Arnold <seth.arnold@canonical.com>
------------ Introduction ------------ AppArmor protects systems from insecure or untrusted processes by running them in restricted confinement, while still allowing processes to share files, exercise privilege and communicate with other processes. AppArmor is a Mandatory Access Control (MAC) mechanism which uses the Linux Security Module (LSM) framework. The confinement's restrictions are mandatory and are not bound to identity, group membership, or object ownership. The protections provided are in addition to the kernel's regular access control mechanisms (including DAC) and can be used to restrict the superuser. The AppArmor kernel module and accompanying user-space tools are available under the GPL license (the exception is the libapparmor library, available under the LGPL license, which allows change_hat(2) and change_profile(2) to be used by non-GPL binaries). For more information, you can read the techdoc.pdf (available after building the parser) and by visiting the http://apparmor.net/ web site. ------------- Source Layout ------------- AppArmor consists of several different parts: changehat/ source for using changehat with Apache, PAM and Tomcat common/ common makefile rules desktop/ empty kernel-patches/ compatibility patches for various kernel versions libraries/ libapparmor source and language bindings parser/ source for parser/loader and corresponding documentation profiles/ configuration files, reference profiles and abstractions tests/ regression and stress testsuites utils/ high-level utilities for working with AppArmor -------------------------------------- Important note on AppArmor kernel code -------------------------------------- While most of the kernel AppArmor code has been accepted in the upstream Linux kernel, a few important pieces were not included. These missing pieces unfortunately are important bits for AppArmor userspace and kernel interaction; therefore we have included compatibility patches in the kernel-patches/ subdirectory, versioned by upstream kernel (2.6.37 patches should apply cleanly to 2.6.38 source). Without these patches applied to the kernel, the AppArmor userspace will not function correctly. ------------------------------------------ Building and Installing AppArmor Userspace ------------------------------------------ To build and install AppArmor userspace on your system, build and install in the following order. libapparmor: $ cd ./libraries/libapparmor $ sh ./autogen.sh $ sh ./configure --prefix=/usr --with-perl --with-python # see below $ make $ make check $ make install [an additional optional argument to libapparmor's configure is --with-ruby, to generate Ruby bindings to libapparmor.] Utilities: $ cd utils $ make $ make check $ make install parser: $ cd parser $ make # depends on libapparmor having been built first $ make check $ make install Apache mod_apparmor: $ cd changehat/mod_apparmor $ make # depends on libapparmor having been built first $ make install PAM AppArmor: $ cd changehat/pam_apparmor $ make # depends on libapparmor having been built first $ make install Profiles: $ cd profiles $ make $ make check # depends on the parser having been built first $ make install [Note that for the parser and the utils, if you only with to build/use some of the locale languages, you can override the default by passing the LANGS arguments to make; e.g. make all install "LANGS=en_US fr".] ------------------- AppArmor Testsuites ------------------- A number of testsuites are in the AppArmor sources. Most have documentation on usage and how to update and add tests. Below is a quick overview of their location and how to run them. Regression tests ---------------- For details on structure and adding tests, see tests/regression/apparmor/README. To run: $ cd tests/regression/apparmor (requires root) $ make $ sudo make tests $ sudo bash open.sh -r # runs and saves the last testcase from open.sh Parser tests ------------ For details on structure and adding tests, see parser/tst/README. To run: $ cd parser/tst $ make $ make tests Libapparmor ----------- For details on structure and adding tests, see libraries/libapparmor/README. $ cd libraries/libapparmor $ make check Utils ----- Tests for the Python utilities exist in the test/ subdirectory. $ cd utils $ make check The aa-decode utility to be tested can be overridden by setting up environment variable APPARMOR_DECODE; e.g.: $ APPARMOR_DECODE=/usr/bin/aa-decode make check Profile checks -------------- A basic consistency check to ensure that the parser and aa-logprof parse successfully the current set of shipped profiles. The system or other parser and logprof can be passed in by overriding the PARSER and LOGPROF variables. $ cd profiles $ make && make check Stress Tests ------------ To run AppArmor stress tests: $ make all Use these: $ ./change_hat $ ./child $ ./kill.sh $ ./open $ ./s.sh Or run all at once: $ ./stress.sh Please note that the above will stress the system so much it may end up invoking the OOM killer. To run parser stress tests (requires /usr/bin/ruby): $ ./stress.sh (see stress.sh -h for options) ----------------------------------------------- Building and Installing AppArmor Kernel Patches ----------------------------------------------- TODO ----------------- Required versions ----------------- The AppArmor userspace utilities are written with some assumptions about installed and available versions of other tools. This is a (possibly incomplete) list of known version dependencies: The Python utilities require a minimum of Python 2.7 or Python 3.3. Some utilities (aa-exec, aa-notify and aa-decode) require Perl 5.10.1 or newer. Most shell scripts are written for POSIX-compatible sh. aa-decode expects bash, probably version 3.2 and higher.