KVM: nVMX: Fix size checks in vmx_set_nested_state

commit e8ab8d2 upstream.

The size checks in vmx_nested_state are wrong because the calculations
are made based on the size of a pointer to a struct kvm_nested_state
rather than the size of a struct kvm_nested_state.

Reported-by: Felix Wilhelm  <fwilhelm@google.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Drew Schmitt <dasch@google.com>
Reviewed-by: Marc Orr <marcorr@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Fixes: 8fcc4b5
Cc: stable@ver.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/x86/kvm/vmx.c

@@ -14236,7 +14236,7 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
 		return ret;
 
 	/* Empty 'VMXON' state is permitted */
-	if (kvm_state->size < sizeof(kvm_state) + sizeof(*vmcs12))
+	if (kvm_state->size < sizeof(*kvm_state) + sizeof(*vmcs12))
 		return 0;
 
 	if (kvm_state->vmx.vmcs_pa == kvm_state->vmx.vmxon_pa ||
@@ -14269,7 +14269,7 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
 	if (nested_cpu_has_shadow_vmcs(vmcs12) &&
 	    vmcs12->vmcs_link_pointer != -1ull) {
 		struct vmcs12 *shadow_vmcs12 = get_shadow_vmcs12(vcpu);
-		if (kvm_state->size < sizeof(kvm_state) + 2 * sizeof(*vmcs12))
+		if (kvm_state->size < sizeof(*kvm_state) + 2 * sizeof(*vmcs12))
 			return -EINVAL;
 
 		if (copy_from_user(shadow_vmcs12,