On Thu, Apr 03, 2014 at 08:04:23PM +0200, Alexander Graf wrote:
>
> On 03.04.2014, at 18:51, Michael S. Tsirkin <[email protected]> wrote:
>
> > From: Michael Roth <[email protected]>
> >
> > CVE-2013-4534
> >
> > opp->nb_cpus is read from the wire and used to determine how many
> > IRQDest elements to read into opp->dst[]. If the value exceeds the
> > length of opp->dst[], MAX_CPU, opp->dst[] can be overrun with arbitrary
> > data from the wire.
> >
> > Fix this by failing migration if the value read from the wire exceeds
> > MAX_CPU.
> >
> > Signed-off-by: Michael Roth <[email protected]>
> > Signed-off-by: Michael S. Tsirkin <[email protected]>
>
> Reviewed-by: Alexander Graf <[email protected]>
>
> Though I don't think the nb_cpus checks are necessary, it's always nice to be
> safe rather than sorry :).
>
>
> Alex
>
> > ---
> > hw/intc/openpic.c | 14 ++++++++++++--
> > 1 file changed, 12 insertions(+), 2 deletions(-)
> >
> > diff --git a/hw/intc/openpic.c b/hw/intc/openpic.c
> > index be76fbd..e63ccf2 100644
> > --- a/hw/intc/openpic.c
> > +++ b/hw/intc/openpic.c
> > @@ -1416,7 +1416,7 @@ static void openpic_load_IRQ_queue(QEMUFile* f,
> > IRQQueue *q)
> > static int openpic_load(QEMUFile* f, void *opaque, int version_id)
> > {
> > OpenPICState *opp = (OpenPICState *)opaque;
> > - unsigned int i;
> > + unsigned int i, nb_cpus;
> >
> > if (version_id != 1) {
> > return -EINVAL;
> > @@ -1428,7 +1428,11 @@ static int openpic_load(QEMUFile* f, void *opaque,
> > int version_id)
> > qemu_get_be32s(f, &opp->spve);
> > qemu_get_be32s(f, &opp->tfrr);
> >
> > - qemu_get_be32s(f, &opp->nb_cpus);
> > + qemu_get_be32s(f, &nb_cpus);
> > + if (opp->nb_cpus != nb_cpus) {
> > + return -EINVAL;
> > + }
> > + assert(nb_cpus > 0 && nb_cpus <= MAX_CPU);
> >
> > for (i = 0; i < opp->nb_cpus; i++) {
> > qemu_get_sbe32s(f, &opp->dst[i].ctpr);
> > @@ -1567,6 +1571,12 @@ static void openpic_realize(DeviceState *dev, Error
> > **errp)
> > {NULL}
> > };
> >
> > + if (opp->nb_cpus > MAX_CPU) {
> > + error_set(errp, QERR_PROPERTY_VALUE_OUT_OF_RANGE,
> > + TYPE_OPENPIC, "nb_cpus", 0, MAX_CPU);
> > + return;
> > + }
> > +
This one causes a warning on 32 bit hosts, will repost a tweaked
version.
> > switch (opp->model) {
> > case OPENPIC_MODEL_FSL_MPIC_20:
> > default:
> > --
> > MST
> >
>
