Hello! My name is Tad. I have a few personal projects for the past five or so years for making available kernel hardening features to more users. My main project is DivestOS, which provides more secure images for older/legacy Android devices. I harden all device kernels via the following: * My automatic CVE checker/patcher program [1]. It is able to apply many dozen to many hundred CVE patches to trees. It is backed by an extensive versioned list [2] of CVE patches that I origianlly maintained by hand. In the past year or so I pull in using a scraper I made for the CIP scripts [3]. * My hardenDefconfig function [4], inspired by the KSPP recommendations and later Popov's kconfig-hardened-check. It simply enables and disables various options. * My hardenBootArgs function [5], currently just enables slub_debug=FZP for devices. * Some misc tweaks [6], currently for disabling slub/slab merging. * And lastly some sysctl tweaks [7]. I also maintain another project for providing some extra security to modern distros, without recompilation. It is called Brace [8] and compatible with Arch/Fedora/Debian/OpenSUSE. In the kernel relations, it is mostly just sysctl [9] changes and kernel commandline [10] changes. Lastly some background: Micay inspired me to work on this area back in mid-2015, after he helped me port his Android PaX patchset to the OnePlus One phone [11]. Sharing for any comments. Also most of you are likely working on mainline, not ancient kernels, so maybe you'll find this interesting. Best regards, Tad. [1] https://gitlab.com/divested-mobile/cve_checker [2] https://gitlab.com/divested-mobile/kernel_patches/-/blob/master/Kernel_CVE_Patch_List.txt [3] https://gitlab.com/cip-project/cip-kernel/cip-kernel-sec [4] https://gitlab.com/divested-mobile/divestos-build/-/blob/e7dd0af4/Scripts/Common/Functions.sh#L657 [5] https://gitlab.com/divested-mobile/divestos-build/-/blob/e7dd0af4/Scripts/Common/Functions.sh#L493 [6] https://gitlab.com/divested-mobile/divestos-build/-/blob/e7dd0af4/Scripts/Common/Post.sh#L28 [7] https://gitlab.com/divested-mobile/divestos-build/-/blob/e7dd0af4/Patches/LineageOS-18.1/android_system_core/0001-Harden.patch [8] https://gitlab.com/divested/brace [9] https://gitlab.com/divested/brace/-/blob/1e4975c9/brace/usr/lib/sysctl.d/60-restrict.conf [10] https://gitlab.com/divested/brace/-/blob/1e4975c9/brace/usr/bin/brace-supplemental-changes#L33 [11] https://divestos.org/images/screenshots/CopperheadOS-bacon.png
