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89b223bfb8
Deprecate the CONFIG_SECURITY_SELINUX_DISABLE functionality. The code was originally developed to make it easier for Linux distributions to support architectures where adding parameters to the kernel command line was difficult. Unfortunately, supporting runtime disable meant we had to make some security trade-offs when it came to the LSM hooks, as documented in the Kconfig help text: NOTE: selecting this option will disable the '__ro_after_init' kernel hardening feature for security hooks. Please consider using the selinux=0 boot parameter instead of enabling this option. Fortunately it looks as if that the original motivation for the runtime disable functionality is gone, and Fedora/RHEL appears to be the only major distribution enabling this capability at build time so we are now taking steps to remove it entirely from the kernel. The first step is to mark the functionality as deprecated and print an error when it is used (what this patch is doing). As Fedora/RHEL makes progress in transitioning the distribution away from runtime disable, we will introduce follow-up patches over several kernel releases which will block for increasing periods of time when the runtime disable is used. Finally we will remove the option entirely once we believe all users have moved to the kernel cmdline approach. Acked-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: Ondrej Mosnacek <omosnace@redhat.com> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Paul Moore <paul@paul-moore.com>
26 lines
1.3 KiB
Text
26 lines
1.3 KiB
Text
What: /sys/fs/selinux/disable
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Date: April 2005 (predates git)
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KernelVersion: 2.6.12-rc2 (predates git)
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Contact: selinux@vger.kernel.org
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Description:
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The selinuxfs "disable" node allows SELinux to be disabled at runtime
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prior to a policy being loaded into the kernel. If disabled via this
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mechanism, SELinux will remain disabled until the system is rebooted.
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The preferred method of disabling SELinux is via the "selinux=0" boot
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parameter, but the selinuxfs "disable" node was created to make it
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easier for systems with primitive bootloaders that did not allow for
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easy modification of the kernel command line. Unfortunately, allowing
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for SELinux to be disabled at runtime makes it difficult to secure the
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kernel's LSM hooks using the "__ro_after_init" feature.
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Thankfully, the need for the SELinux runtime disable appears to be
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gone, the default Kconfig configuration disables this selinuxfs node,
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and only one of the major distributions, Fedora, supports disabling
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SELinux at runtime. Fedora is in the process of removing the
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selinuxfs "disable" node and once that is complete we will start the
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slow process of removing this code from the kernel.
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More information on /sys/fs/selinux/disable can be found under the
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CONFIG_SECURITY_SELINUX_DISABLE Kconfig option.
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