On 23/10/2017 14:39, Cornelia Huck wrote: > On Mon, 23 Oct 2017 11:52:51 +0200 > David Hildenbrand <david@xxxxxxxxxx> wrote: > >> On 21.10.2017 01:25, Paolo Bonzini wrote: >>> Two KVM ioctls (KVM_GET/SET_CPUID2) directly access the cpuid_entries >>> field of struct kvm_vcpu_arch. Therefore, the new usercopy hardening >>> work in linux-next, which forbids copies from and to slab objects >>> unless they are from kmalloc or explicitly whitelisted, breaks KVM >>> completely. >>> >>> This series fixes it by adding the two new usercopy arguments >>> to kvm_init (more precisely to a new function kvm_init_usercopy, >>> while kvm_init passes zeroes as a default). >>> >>> There's also another broken ioctl, KVM_XEN_HVM_CONFIG, but it is >>> obsolete and not a big deal at all. >>> >>> I'm Ccing all submaintainers in case they have something similar >>> going on in their kvm_arch and kvm_vcpu_arch structs. KVM has a >>> pretty complex userspace API, so thorough with linux-next is highly >>> recommended. >> >> I assume on s390x, at least >> >> kvm_arch_vcpu_ioctl_get_one_reg() and >> kvm_arch_vcpu_ioctl_set_one_reg() >> >> have to be fixed. > > At a glance, seems like it. > >> >> Christian, are you already looking into this? > > I'm afraid I'm also busy with travel preparation/travel, so I'd be glad > for any takers. Let's do a generic fix now, so that we don't need to rush the switch to explicit whitelisting. Paolo
