linux-arm.git - Russell King's ARM Linux kernel tree

Age	Commit message (Collapse)	Author
2023-03-20	selinux: remove the runtime disable functionality	Paul Moore
	After working with the larger SELinux-based distros for several years, we're finally at a place where we can disable the SELinux runtime disable functionality. The existing kernel deprecation notice explains the functionality and why we want to remove it: The selinuxfs "disable" node allows SELinux to be disabled at runtime prior to a policy being loaded into the kernel. If disabled via this mechanism, SELinux will remain disabled until the system is rebooted. The preferred method of disabling SELinux is via the "selinux=0" boot parameter, but the selinuxfs "disable" node was created to make it easier for systems with primitive bootloaders that did not allow for easy modification of the kernel command line. Unfortunately, allowing for SELinux to be disabled at runtime makes it difficult to secure the kernel's LSM hooks using the "__ro_after_init" feature. It is that last sentence, mentioning the '__ro_after_init' hardening, which is the real motivation for this change, and if you look at the diffstat you'll see that the impact of this patch reaches across all the different LSMs, helping prevent tampering at the LSM hook level. From a SELinux perspective, it is important to note that if you continue to disable SELinux via "/etc/selinux/config" it may appear that SELinux is disabled, but it is simply in an uninitialized state. If you load a policy with `load_policy -i`, you will see SELinux come alive just as if you had loaded the policy during early-boot. It is also worth noting that the "/sys/fs/selinux/disable" file is always writable now, regardless of the Kconfig settings, but writing to the file has no effect on the system, other than to display an error on the console if a non-zero/true value is written. Finally, in the several years where we have been working on deprecating this functionality, there has only been one instance of someone mentioning any user visible breakage. In this particular case it was an individual's kernel test system, and the workaround documented in the deprecation notice ("selinux=0" on the kernel command line) resolved the issue without problem. Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-11-06	bpf: Implement task local storage	KP Singh
	Similar to bpf_local_storage for sockets and inodes add local storage for task_struct. The life-cycle of storage is managed with the life-cycle of the task_struct. i.e. the storage is destroyed along with the owning task with a callback to the bpf_task_storage_free from the task_free LSM hook. The BPF LSM allocates an __rcu pointer to the bpf_local_storage in the security blob which are now stackable and can co-exist with other LSMs. The userspace map operations can be done by using a pid fd as a key passed to the lookup, update and delete operations. Signed-off-by: KP Singh <kpsingh@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20201106103747.2780972-3-kpsingh@chromium.org
2020-08-25	bpf: Implement bpf_local_storage for inodes	KP Singh
	Similar to bpf_local_storage for sockets, add local storage for inodes. The life-cycle of storage is managed with the life-cycle of the inode. i.e. the storage is destroyed along with the owning inode. The BPF LSM allocates an __rcu pointer to the bpf_local_storage in the security blob which are now stackable and can co-exist with other LSMs. Signed-off-by: KP Singh <kpsingh@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200825182919.1118197-6-kpsingh@chromium.org
2020-03-30	bpf: lsm: Initialize the BPF LSM hooks	KP Singh
	* The hooks are initialized using the definitions in include/linux/lsm_hook_defs.h. * The LSM can be enabled / disabled with CONFIG_BPF_LSM. Signed-off-by: KP Singh <kpsingh@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Brendan Jackman <jackmanb@google.com> Reviewed-by: Florent Revest <revest@google.com> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: James Morris <jamorris@linux.microsoft.com> Link: https://lore.kernel.org/bpf/20200329004356.27286-6-kpsingh@chromium.org