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 <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
---
v2: move CONFIG_CFI_CLANG=y to global config
v1: https://lore.kernel.org/all/[email protected]/
---
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