a0871be6c0
* Update buildroot-patches for 2020.11-rc1 buildroot * Update buildroot to 2020.11-rc1 Signed-off-by: Stefan Agner <stefan@agner.ch> * Don't rely on sfdisk --list-free output The --list-free (-F) argument does not allow machine readable mode. And it seems that the output format changes over time (different spacing, using size postfixes instead of raw blocks). Use sfdisk json output and calculate free partition space ourselfs. This works for 2.35 and 2.36 and is more robust since we rely on output which is meant for scripts to parse. * Migrate defconfigs for Buildroot 2020.11-rc1 In particular, rename BR2_TARGET_UBOOT_BOOT_SCRIPT(_SOURCE) to BR2_PACKAGE_HOST_UBOOT_TOOLS_BOOT_SCRIPT(_SOURCE). * Rebase/remove systemd patches for systemd 246 * Drop apparmor/libapparmor from buildroot-external * hassos-persists: use /run as directory for lockfiles The U-Boot tools use /var/lock by default which is not created any more by systemd by default (it is under tmpfiles legacy.conf, which we no longer install). * Disable systemd-update-done.service The service is not suited for pure read-only systems. In particular the service needs to be able to write a file in /etc and /var. Remove the service. Note: This is a static service and cannot be removed using systemd-preset. * Disable apparmor.service for now The service loads all default profiles. Some might actually cause problems. E.g. the profile for ping seems not to match our setup for /etc/resolv.conf: [85503.634653] audit: type=1400 audit(1605286002.684:236): apparmor="DENIED" operation="open" profile="ping" name="/run/resolv.conf" pid=27585 comm="ping" requested_mask="r" denied_mask="r" fsuid=0 ouid=0
75 lines
2.9 KiB
Plaintext
75 lines
2.9 KiB
Plaintext
// -*- mode:doc; -*-
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// vim: set syntax=asciidoc:
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[[selinux]]
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== Using SELinux in Buildroot
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https://selinuxproject.org[SELinux] is a Linux kernel security module
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enforcing access control policies. In addition to the traditional file
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permissions and access control lists, +SELinux+ allows to write rules
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for users or processes to access specific functions of resources
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(files, sockets...).
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_SELinux_ has three modes of operation:
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* _Disabled_: the policy is not applied
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* _Permissive_: the policy is applied, and non-authorized actions are
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simply logged. This mode is often used for troubleshooting SELinux
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issues.
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* _Enforcing_: the policy is applied, and non-authorized actions are
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denied
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In Buildroot the mode of operation is controlled by the
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+BR2_PACKAGE_REFPOLICY_POLICY_STATE_*+ configuration options. The
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Linux kernel also has various configuration options that affect how
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+SELinux+ is enabled (see +security/selinux/Kconfig+ in the Linux
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kernel sources).
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By default in Buildroot the +SELinux+ policy is provided by the
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upstream https://github.com/SELinuxProject/refpolicy[refpolicy]
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project, enabled with +BR2_PACKAGE_REFPOLICY+.
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[[enabling-selinux]]
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=== Enabling SELinux support
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To have proper support for +SELinux+ in a Buildroot generated system,
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the following configuration options must be enabled:
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* +BR2_PACKAGE_LIBSELINUX+
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* +BR2_PACKAGE_REFPOLICY+
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In addition, your filesystem image format must support extended
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attributes.
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[[selinux-policy-tweaking]]
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=== SELinux policy tweaking
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The +SELinux refpolicy+ contains modules that can be enabled or
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disabled when being built. Each module provide a number of +SELinux+
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rules. In Buildroot the non-base modules are disabled by default and
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several ways to enable such modules are provided:
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- Packages can enable a list of +SELinux+ modules within the +refpolicy+ using
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the +<packagename>_SELINUX_MODULES+ variable.
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- Packages can provide additional +SELinux+ modules by putting them (.fc, .if
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and .te files) in +package/<packagename>/selinux/+.
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- Extra +SELinux+ modules can be added in directories pointed by the
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+BR2_REFPOLICY_EXTRA_MODULES_DIRS+ configuration option.
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- Additional modules in the +refpolicy+ can be enabled if listed in the
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+BR2_REFPOLICY_EXTRA_MODULES_DEPENDENCIES+ configuration option.
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Buildroot also allows to completely override the +refpolicy+. This
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allows to provide a full custom policy designed specifically for a
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given system. When going this way, all of the above mechanisms are
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disabled: no extra +SElinux+ module is added to the policy, and all
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the available modules within the custom policy are enabled and built
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into the final binary policy. The custom policy must be a fork of the
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official https://github.com/SELinuxProject/refpolicy[refpolicy].
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In order to fully override the +refpolicy+ the following configuration
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variables have to be set:
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- +BR2_PACKAGE_REFPOLICY_CUSTOM_GIT+
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- +BR2_PACKAGE_REFPOLICY_CUSTOM_REPO_URL+
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- +BR2_PACKAGE_REFPOLICY_CUSTOM_REPO_VERSION+
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