Re: [PATCH 3/3] [RFC V3] KVM: X86: Adding skeleton for Memory ROE
From: Randy Dunlap <rdunlap@infradead.org>
Date: 2018-07-20 01:08:16
Also in:
kvm, linux-doc
On 07/19/2018 02:38 PM, Ahmed Abd El Mawgood wrote:
This patch introduces a hypercall implemented for X86 that can assist against subset of kernel rootkits, it works by place readonly protection in shadow PTE. The end result protection is also kept in a bitmap for each kvm_memory_slot and is used as reference when updating SPTEs. The whole goal is to protect the guest kernel static data from modification if attacker is running from guest ring 0, for this reason there is no hypercall to revert effect of Memory ROE hypercall. This patch doesn't implement integrity check on guest TLB so obvious attack on the current implementation will involve guest virtual address -> guest physical address remapping, but there are plans to fix that. Signed-off-by: Ahmed Abd El Mawgood <redacted> ---
quoted hunk
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig index 92fd433c50b9..8ae822a8dc7a 100644 --- a/arch/x86/kvm/Kconfig +++ b/arch/x86/kvm/Kconfig@@ -96,6 +96,13 @@ config KVM_MMU_AUDIT This option adds a R/W kVM module parameter 'mmu_audit', which allows auditing of KVM MMU events at runtime. +config KVM_MROE + bool "Hypercall Memory Read-Only Enforcement" + depends on KVM && X86 + help + This option add KVM_HC_HMROE hypercall to kvm which as hardening
adds to kvm as a hardening (???)
quoted hunk
+ mechanism to protect memory pages from being edited. + # OK, it's a little counter-intuitive to do this, but it puts it neatly under # the virtualization menu. source drivers/vhost/Kconfig
-- ~Randy