Re: [PATCH] KVM: dereference of NULL pointer in set_pal_result()
Gabor Gombas <[email protected]>
| Newsgroups | org.kernel.vger.kvm-ia64,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
On Fri, Jan 08, 2010 at 07:28:57AM +0800, Zhang, Xiantao wrote:
> For the check "(p && p->exit_reason = EXIT_REASON_PAL_CALL", if p is NULL, the reference about "p->exit_reason = EXIT_REASON_PAL_CALL" won't be checked any more, so no issue here.
> > diff --git a/arch/ia64/kvm/kvm_fw.c b/arch/ia64/kvm/kvm_fw.c
> > index e4b8231..d28494f 100644
> > --- a/arch/ia64/kvm/kvm_fw.c
> > +++ b/arch/ia64/kvm/kvm_fw.c
> > @@ -75,9 +75,11 @@ static void set_pal_result(struct kvm_vcpu *vcpu,
> > struct exit_ctl_data *p;
> >
> > p = kvm_get_exit_data(vcpu);
> > - if (p && p->exit_reason = EXIT_REASON_PAL_CALL) {
> > + if (!p)
> > + return;
> > + if (p->exit_reason = EXIT_REASON_PAL_CALL) {
> > p->u.pal_data.ret = result;
> > - return ;
> > + return;
> > }
> > INIT_PAL_STATUS_UNIMPLEMENTED(p->u.pal_data.ret);
IMHO it's not the test but the INIT_PAL_STATUS_UNIMPLEMENTED() that does
the unwanted dereferencing, and that's fixed by the patch.
Gabor
--
---------------------------------------------------------
MTA SZTAKI Computer and Automation Research Institute
Hungarian Academy of Sciences
---------------------------------------------------------