From a284e43852380ab71eeb996389e01992d74a8dde Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 1 May 2024 12:37:12 -0700 Subject: [PATCH] hardening: Enable KCFI and some other options Add some stuff that got missed along the way: - CONFIG_UNWIND_PATCH_PAC_INTO_SCS=y so SCS vs PAC is hardware selectable. - CONFIG_X86_KERNEL_IBT=y while a default, just be sure. - CONFIG_CFI_CLANG=y globally. - CONFIG_PAGE_TABLE_CHECK=y for userspace mapping sanity. Reviewed-by: Nathan Chancellor Link: https://lore.kernel.org/r/20240501193709.make.982-kees@kernel.org Signed-off-by: Kees Cook --- arch/arm64/configs/hardening.config | 1 + arch/x86/configs/hardening.config | 3 +++ kernel/configs/hardening.config | 8 ++++++++ 3 files changed, 12 insertions(+) diff --git a/arch/arm64/configs/hardening.config b/arch/arm64/configs/hardening.config index b0e7952089983..24179722927e1 100644 --- a/arch/arm64/configs/hardening.config +++ b/arch/arm64/configs/hardening.config @@ -5,6 +5,7 @@ CONFIG_ARM64_SW_TTBR0_PAN=y # Software Shadow Stack or PAC CONFIG_SHADOW_CALL_STACK=y +CONFIG_UNWIND_PATCH_PAC_INTO_SCS=y # Pointer authentication (ARMv8.3 and later). If hardware actually supports # it, one can turn off CONFIG_STACKPROTECTOR_STRONG with this enabled. diff --git a/arch/x86/configs/hardening.config b/arch/x86/configs/hardening.config index 7b497f3b7bc3c..de319852a1e9d 100644 --- a/arch/x86/configs/hardening.config +++ b/arch/x86/configs/hardening.config @@ -10,5 +10,8 @@ CONFIG_INTEL_IOMMU_DEFAULT_ON=y CONFIG_INTEL_IOMMU_SVM=y CONFIG_AMD_IOMMU=y +# Enforce CET Indirect Branch Tracking in the kernel. +CONFIG_X86_KERNEL_IBT=y + # Enable CET Shadow Stack for userspace. CONFIG_X86_USER_SHADOW_STACK=y diff --git a/kernel/configs/hardening.config b/kernel/configs/hardening.config index 7a5bbfc024b7d..47e6564129c32 100644 --- a/kernel/configs/hardening.config +++ b/kernel/configs/hardening.config @@ -23,6 +23,10 @@ CONFIG_SLAB_FREELIST_HARDENED=y CONFIG_SHUFFLE_PAGE_ALLOCATOR=y CONFIG_RANDOM_KMALLOC_CACHES=y +# Sanity check userspace page table mappings. +CONFIG_PAGE_TABLE_CHECK=y +CONFIG_PAGE_TABLE_CHECK_ENFORCED=y + # Randomize kernel stack offset on syscall entry. CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT=y @@ -81,6 +85,10 @@ CONFIG_SECCOMP_FILTER=y # Provides some protections against SYN flooding. CONFIG_SYN_COOKIES=y +# Enable Kernel Control Flow Integrity (currently Clang only). +CONFIG_CFI_CLANG=y +# CONFIG_CFI_PERMISSIVE is not set + # Attack surface reduction: do not autoload TTY line disciplines. # CONFIG_LDISC_AUTOLOAD is not set -- 2.30.2