KVM: x86: fix wbinvd_dirty_mask use-after-free

commit bd768e1466 upstream.

vcpu->arch.wbinvd_dirty_mask may still be used after freeing it,
corrupting memory. For example, the following call trace may set a bit
in an already freed cpu mask:
    kvm_arch_vcpu_load
    vcpu_load
    vmx_free_vcpu_nested
    vmx_free_vcpu
    kvm_arch_vcpu_free

Fix this by deferring freeing of wbinvd_dirty_mask.

Signed-off-by: Ido Yariv <ido@wizery.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ido Yariv
2016-10-21 12:39:57 -04:00
committed by Greg Kroah-Hartman
parent cb270a3f16
commit 159766dff4

View File

@@ -7252,10 +7252,12 @@ void kvm_put_guest_fpu(struct kvm_vcpu *vcpu)
void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
{
void *wbinvd_dirty_mask = vcpu->arch.wbinvd_dirty_mask;
kvmclock_reset(vcpu);
free_cpumask_var(vcpu->arch.wbinvd_dirty_mask);
kvm_x86_ops->vcpu_free(vcpu);
free_cpumask_var(wbinvd_dirty_mask);
}
struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,