| Message ID | 1412936070-18860-3-git-send-email-christoffer.dall@linaro.org |
|---|---|
| State | New |
| Headers | show |
On Fri, Oct 10, 2014 at 11:14:29AM +0100, Christoffer Dall wrote: > 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. > > Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
On 2014-10-10 11:14, Christoffer Dall wrote: > 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. > > Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> Acked-by: Marc Zyngier <marc.zyngier@arm.com> M.
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index 6e87233..d664bff 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -994,6 +994,9 @@ 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; @@ -1218,6 +1221,11 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, struct kvm_userspace_memory_region *mem, enum kvm_mr_change change) { + if (change == KVM_MR_CREATE || change == KVM_MR_MOVE) { + if (memslot->base_gfn + memslot->npages >= + (KVM_PHYS_SIZE >> PAGE_SHIFT)) + return -EFAULT; + } return 0; }
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. Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> --- arch/arm/kvm/mmu.c | 8 ++++++++ 1 file changed, 8 insertions(+)