This is a note to let you know that I've just added the patch titled
[Variant 3/Meltdown] arm64: Kconfig: Add CONFIG_UNMAP_KERNEL_AT_EL0
to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: arm64-kconfig-add-config_unmap_kernel_at_el0.patch and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Tue Feb 13 17:25:10 CET 2018
From: Will Deacon will.deacon@arm.com Date: Tue, 14 Nov 2017 14:41:01 +0000 Subject: [Variant 3/Meltdown] arm64: Kconfig: Add CONFIG_UNMAP_KERNEL_AT_EL0
From: Will Deacon will.deacon@arm.com
Commit 084eb77cd3a8 upstream.
Add a Kconfig entry to control use of the entry trampoline, which allows us to unmap the kernel whilst running in userspace and improve the robustness of KASLR.
Reviewed-by: Mark Rutland mark.rutland@arm.com Tested-by: Laura Abbott labbott@redhat.com Tested-by: Shanker Donthineni shankerd@codeaurora.org Signed-off-by: Will Deacon will.deacon@arm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/Kconfig | 13 +++++++++++++ 1 file changed, 13 insertions(+)
--- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -843,6 +843,19 @@ config FORCE_MAX_ZONEORDER However for 4K, we choose a higher default value, 11 as opposed to 10, giving us 4M allocations matching the default size used by generic code.
+config UNMAP_KERNEL_AT_EL0 + bool "Unmap kernel when running in userspace (aka "KAISER")" + default y + help + Some attacks against KASLR make use of the timing difference between + a permission fault which could arise from a page table entry that is + present in the TLB, and a translation fault which always requires a + page table walk. This option defends against these attacks by unmapping + the kernel whilst running in userspace, therefore forcing translation + faults for all of kernel space. + + If unsure, say Y. + menuconfig ARMV8_DEPRECATED bool "Emulate deprecated/obsolete ARMv8 instructions" depends on COMPAT
Patches currently in stable-queue which might be from will.deacon@arm.com are
queue-4.15/arm64-make-user_ds-an-inclusive-limit.patch queue-4.15/arm64-mm-remove-pre_ttbr0_update_workaround-for-falkor-erratum-e1003.patch queue-4.15/arm64-uaccess-don-t-bother-eliding-access_ok-checks-in-__-get-put-_user.patch queue-4.15/arm64-cpufeature-pass-capability-structure-to-enable-callback.patch queue-4.15/arm64-uaccess-mask-__user-pointers-for-__arch_-clear-copy_-_user.patch queue-4.15/arm64-mm-add-arm64_kernel_unmapped_at_el0-helper.patch queue-4.15/arm64-entry-reword-comment-about-post_ttbr_update_workaround.patch queue-4.15/arm64-kaslr-put-kernel-vectors-address-in-separate-data-page.patch queue-4.15/arm-arm64-smccc-make-function-identifiers-an-unsigned-quantity.patch queue-4.15/arm64-move-bp-hardening-to-check_and_switch_context.patch queue-4.15/arm-arm64-kvm-advertise-smccc-v1.1.patch queue-4.15/arm64-move-post_ttbr_update_workaround-to-c-code.patch queue-4.15/arm64-turn-on-kpti-only-on-cpus-that-need-it.patch queue-4.15/firmware-psci-expose-psci-conduit.patch queue-4.15/arm64-force-kpti-to-be-disabled-on-cavium-thunderx.patch queue-4.15/arm64-entry-apply-bp-hardening-for-high-priority-synchronous-exceptions.patch queue-4.15/arm64-kpti-fix-the-interaction-between-asid-switching-and-software-pan.patch queue-4.15/firmware-psci-expose-smccc-version-through-psci_ops.patch queue-4.15/arm64-mm-permit-transitioning-from-global-to-non-global-without-bbm.patch queue-4.15/arm64-mm-allocate-asids-in-pairs.patch queue-4.15/arm64-tls-avoid-unconditional-zeroing-of-tpidrro_el0-for-native-tasks.patch queue-4.15/arm64-use-ret-instruction-for-exiting-the-trampoline.patch queue-4.15/arm64-futex-mask-__user-pointers-prior-to-dereference.patch queue-4.15/arm64-entry-explicitly-pass-exception-level-to-kernel_ventry-macro.patch queue-4.15/arm64-implement-branch-predictor-hardening-for-affected-cortex-a-cpus.patch queue-4.15/arm64-kpti-make-use-of-ng-dependent-on-arm64_kernel_unmapped_at_el0.patch queue-4.15/arm-arm64-kvm-add-psci_version-helper.patch queue-4.15/arm64-kill-psci_get_version-as-a-variant-2-workaround.patch queue-4.15/arm64-entry-ensure-branch-through-syscall-table-is-bounded-under-speculation.patch queue-4.15/arm64-mm-use-non-global-mappings-for-kernel-space.patch queue-4.15/arm64-entry-apply-bp-hardening-for-suspicious-interrupts-from-el0.patch queue-4.15/arm64-capabilities-handle-duplicate-entries-for-a-capability.patch queue-4.15/arm64-entry-hook-up-entry-trampoline-to-exception-vectors.patch queue-4.15/arm64-branch-predictor-hardening-for-cavium-thunderx2.patch queue-4.15/arm64-uaccess-prevent-speculative-use-of-the-current-addr_limit.patch queue-4.15/arm64-use-pointer-masking-to-limit-uaccess-speculation.patch queue-4.15/arm64-add-arm_smccc_arch_workaround_1-bp-hardening-support.patch queue-4.15/arm64-erratum-work-around-falkor-erratum-e1003-in-trampoline-code.patch queue-4.15/arm64-mm-fix-and-re-enable-arm64_sw_ttbr0_pan.patch queue-4.15/arm64-mm-invalidate-both-kernel-and-user-asids-when-performing-tlbi.patch queue-4.15/drivers-firmware-expose-psci_get_version-through-psci_ops-structure.patch queue-4.15/arm64-mm-rename-post_ttbr0_update_workaround.patch queue-4.15/arm64-mm-map-entry-trampoline-into-trampoline-and-kernel-page-tables.patch queue-4.15/arm-arm64-kvm-turn-kvm_psci_version-into-a-static-inline.patch queue-4.15/arm-arm64-kvm-implement-psci-1.0-support.patch queue-4.15/arm64-kconfig-reword-unmap_kernel_at_el0-kconfig-entry.patch queue-4.15/arm64-mm-move-asid-from-ttbr0-to-ttbr1.patch queue-4.15/arm64-mm-introduce-ttbr_asid_mask-for-getting-at-the-asid-in-the-ttbr.patch queue-4.15/arm64-kvm-add-smccc_arch_workaround_1-fast-handling.patch queue-4.15/arm64-take-into-account-id_aa64pfr0_el1.csv3.patch queue-4.15/arm64-cputype-add-missing-midr-values-for-cortex-a72-and-cortex-a75.patch queue-4.15/arm64-kvm-report-smccc_arch_workaround_1-bp-hardening-support.patch queue-4.15/arm64-barrier-add-csdb-macros-to-control-data-value-prediction.patch queue-4.15/arm-arm64-smccc-implement-smccc-v1.1-inline-primitive.patch queue-4.15/perf-arm_spe-fail-device-probe-when-arm64_kernel_unmapped_at_el0.patch queue-4.15/arm64-implement-branch-predictor-hardening-for-falkor.patch queue-4.15/arm64-kconfig-add-config_unmap_kernel_at_el0.patch queue-4.15/arm64-idmap-use-awx-flags-for-.idmap.text-.pushsection-directives.patch queue-4.15/arm64-run-enable-method-for-errata-work-arounds-on-late-cpus.patch queue-4.15/arm64-mm-temporarily-disable-arm64_sw_ttbr0_pan.patch queue-4.15/arm64-entry-add-exception-trampoline-page-for-exceptions-from-el0.patch queue-4.15/arm64-kvm-make-psci_version-a-fast-path.patch queue-4.15/arm64-cpufeature-__this_cpu_has_cap-shouldn-t-stop-early.patch queue-4.15/arm64-implement-array_index_mask_nospec.patch queue-4.15/arm64-kpti-add-enable-callback-to-remap-swapper-using-ng-mappings.patch queue-4.15/arm-arm64-kvm-consolidate-the-psci-include-files.patch queue-4.15/arm64-add-skeleton-to-harden-the-branch-predictor-against-aliasing-attacks.patch queue-4.15/arm64-cpu_errata-add-kryo-to-falkor-1003-errata.patch queue-4.15/arm-arm64-kvm-add-smccc-accessors-to-psci-code.patch queue-4.15/arm64-entry-add-fake-cpu-feature-for-unmapping-the-kernel-at-el0.patch queue-4.15/arm64-kvm-use-per-cpu-vector-when-bp-hardening-is-enabled.patch queue-4.15/arm64-cputype-add-midr-values-for-cavium-thunderx2-cpus.patch queue-4.15/arm64-kvm-increment-pc-after-handling-an-smc-trap.patch