From 215199e3d9f3dc01a6d10b8229891e6f7f1085e7 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 24 Aug 2023 21:25:55 -0700 Subject: hardening: Provide Kconfig fragments for basic options Inspired by Salvatore Mesoraca's earlier[1] efforts to provide some in-tree guidance for kernel hardening Kconfig options, add a new fragment named "hardening-basic.config" (along with some arch-specific fragments) that enable a basic set of kernel hardening options that have the least (or no) performance impact and remove a reasonable set of legacy APIs. Using this fragment is as simple as running "make hardening.config". More extreme fragments can be added[2] in the future to cover all the recognized hardening options, and more per-architecture files can be added too. For now, document the fragments directly via comments. Perhaps .rst documentation can be generated from them in the future (rather than the other way around). [1] https://lore.kernel.org/kernel-hardening/1536516257-30871-1-git-send-email-s.mesoraca16@gmail.com/ [2] https://github.com/KSPP/linux/issues/14 Cc: Salvatore Mesoraca Cc: x86@kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-doc@vger.kernel.org Cc: linux-kbuild@vger.kernel.org Signed-off-by: Kees Cook --- arch/x86/configs/hardening.config | 15 +++++++++++++++ 1 file changed, 15 insertions(+) create mode 100644 arch/x86/configs/hardening.config (limited to 'arch/x86/configs') diff --git a/arch/x86/configs/hardening.config b/arch/x86/configs/hardening.config new file mode 100644 index 000000000000..19bb0c7a7669 --- /dev/null +++ b/arch/x86/configs/hardening.config @@ -0,0 +1,15 @@ +# Basic kernel hardening options (specific to x86) + +# Modern libc no longer needs a fixed-position mapping in userspace, remove +# it as a possible target. +CONFIG_LEGACY_VSYSCALL_NONE=y + +# Enable chip-specific IOMMU support. +CONFIG_INTEL_IOMMU=y +CONFIG_INTEL_IOMMU_DEFAULT_ON=y +CONFIG_INTEL_IOMMU_SVM=y +CONFIG_AMD_IOMMU=y +CONFIG_AMD_IOMMU_V2=y + +# Enable CET Shadow Stack for userspace. +CONFIG_X86_USER_SHADOW_STACK=y -- cgit v1.2.3 From faed498d0db78adc1eee6bab3a8480bcb7e17e6e Mon Sep 17 00:00:00 2001 From: Lukas Bulwahn Date: Thu, 12 Oct 2023 06:50:40 +0200 Subject: hardening: x86: drop reference to removed config AMD_IOMMU_V2 Commit 5a0b11a180a9 ("iommu/amd: Remove iommu_v2 module") removes the config AMD_IOMMU_V2. Remove the reference to this config in the x86 architecture-specific hardening config fragment as well. Signed-off-by: Lukas Bulwahn Reviewed-by: Vasant Hegde Link: https://lore.kernel.org/r/20231012045040.22088-1-lukas.bulwahn@gmail.com Signed-off-by: Kees Cook --- arch/x86/configs/hardening.config | 1 - 1 file changed, 1 deletion(-) (limited to 'arch/x86/configs') diff --git a/arch/x86/configs/hardening.config b/arch/x86/configs/hardening.config index 19bb0c7a7669..7b497f3b7bc3 100644 --- a/arch/x86/configs/hardening.config +++ b/arch/x86/configs/hardening.config @@ -9,7 +9,6 @@ CONFIG_INTEL_IOMMU=y CONFIG_INTEL_IOMMU_DEFAULT_ON=y CONFIG_INTEL_IOMMU_SVM=y CONFIG_AMD_IOMMU=y -CONFIG_AMD_IOMMU_V2=y # Enable CET Shadow Stack for userspace. CONFIG_X86_USER_SHADOW_STACK=y -- cgit v1.2.3