From: Christoffer Dall <christoffer.dall@xxxxxxxxxx> When creating or moving a memslot, make sure the IPA space is within the addressable range of the guest. Otherwise, user space can create too large a memslot and KVM would try to access potentially unallocated page table entries when inserting entries in the Stage-2 page tables. Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx> Acked-by: Marc Zyngier <marc.zyngier@xxxxxxx> Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx> --- arch/arm/kvm/mmu.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index ee142ed..8c40829 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -1003,6 +1003,9 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run) goto out_unlock; } + /* Userspace should not be able to register out-of-bounds IPAs */ + VM_BUG_ON(fault_ipa >= KVM_PHYS_SIZE); + ret = user_mem_abort(vcpu, fault_ipa, memslot, hva, fault_status); if (ret == 0) ret = 1; @@ -1229,6 +1232,14 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, return 0; /* + * Prevent userspace from creating a memory region outside of the IPA + * space addressable by the KVM guest IPA space. + */ + if (memslot->base_gfn + memslot->npages >= + (KVM_PHYS_SIZE >> PAGE_SHIFT)) + return -EFAULT; + + /* * A memory region could potentially cover multiple VMAs, and any holes * between them, so iterate over all of them to find out if we can map * any of them right now. -- 2.1.1 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
