[PATHv11 17/43] net: sandbox: fix NULL pointer derefences

[Tom Rini]

On Sat, Dec 02, 2023 at 11:33:14AM -0700, Simon Glass wrote:
> Hi Maxim,
> 
> On Mon, 27 Nov 2023 at 11:20, Tom Rini <trini at konsulko.com> wrote:
> >
> > On Mon, Nov 27, 2023 at 06:57:00PM +0600, Maxim Uvarov wrote:
> > > Add additional checks for NULL pointers.
> > >
> > > Signed-off-by: Maxim Uvarov <maxim.uvarov at linaro.org>
> > > ---
> > >  drivers/net/sandbox.c | 5 +++++
> > >  1 file changed, 5 insertions(+)
> > >
> > > diff --git a/drivers/net/sandbox.c b/drivers/net/sandbox.c
> > > index 13022addb6..75d32db3a9 100644
> > > --- a/drivers/net/sandbox.c
> > > +++ b/drivers/net/sandbox.c
> > > @@ -65,6 +65,9 @@ int sandbox_eth_arp_req_to_reply(struct udevice *dev, void *packet,
> > >       struct ethernet_hdr *eth_recv;
> > >       struct arp_hdr *arp_recv;
> > >
> > > +     if (!priv)
> > > +             return -EAGAIN;
> > > +
> > >       if (ntohs(eth->et_protlen) != PROT_ARP)
> > >               return -EAGAIN;
> >
> > This part seems fine.
> >
> > > @@ -82,6 +85,8 @@ int sandbox_eth_arp_req_to_reply(struct udevice *dev, void *packet,
> > >
> > >       /* Formulate a fake response */
> > >       eth_recv = (void *)priv->recv_packet_buffer[priv->recv_packets];
> > > +     if (!eth_recv)
> > > +             return -EAGAIN;
> > >       memcpy(eth_recv->et_dest, eth->et_src, ARP_HLEN);
> > >       memcpy(eth_recv->et_src, priv->fake_host_hwaddr, ARP_HLEN);
> > >       eth_recv->et_protlen = htons(PROT_ARP);
> >
> > How do we get to this dereference, and is that not a bug in the caller?
> 
> I wonder if somehow the device has not been probed yet?

Given the failures on a number of real hardware platforms in v11 as well
(which I didn't see until after my review), I wonder if you've not
spotted the cause of all of those other failures?

-- 
Tom
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