Messages in this thread Patch in this message | | | From | Kees Cook <> | Subject | [PATCH v2] hardening: Enable KCFI and some other options | Date | Tue, 30 Apr 2024 10:37:00 -0700 |
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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. (And disable FINEIBT since it isn't as secure as straight KCFI.)
- CONFIG_PAGE_TABLE_CHECK=y for userspace mapping sanity.
Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> --- v2: move CONFIG_CFI_CLANG=y to global config v1: https://lore.kernel.org/all/20240426222940.work.884-kees@kernel.org/ --- arch/arm64/configs/hardening.config | 1 + arch/x86/configs/hardening.config | 6 ++++++ kernel/configs/hardening.config | 8 ++++++++ 3 files changed, 15 insertions(+)
diff --git a/arch/arm64/configs/hardening.config b/arch/arm64/configs/hardening.config index b0e795208998..24179722927e 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 7b497f3b7bc3..bf3d31618e12 100644 --- a/arch/x86/configs/hardening.config +++ b/arch/x86/configs/hardening.config @@ -10,5 +10,11 @@ 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 + +# When CONFIG_CFI_CLANG is enabled, disable weaker FINEIBT landing pads. +# CONFIG_FINEIBT is not set diff --git a/kernel/configs/hardening.config b/kernel/configs/hardening.config index 7a5bbfc024b7..47e6564129c3 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 -- 2.34.1
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