[PATCH] lib: utils/irqchip: Add sanity checks to imsic_warm_irqchip_init()

[Anup Patel]

On Wed, May 8, 2024 at 12:23 PM Cyan Yang <cyan.yang at sifive.com> wrote:
>
> On Tue, May 07, 2024 at 06:09:25PM +0530, Anup Patel wrote:
> > On Tue, Apr 9, 2024 at 8:25 PM Cyan Yang <cyan.yang at sifive.com> wrote:
> > >
> > > Add sanity checks for per-HART IMSIC pointer in warm init flow, similar to
> > > what the cold init flow does. This will help prevent any misuse of the
> > > data in scratch space.
> >
> > Can you elaborate on the kind of misuse which can happen ?
> >
>
> We found a case that if a caller misused this function on a platform without
> imsic, the extra check will be needed here since "imsic_get_data()" will not
> guarantee to return a null pointer.
>
> It's not a normal case, of course, but since this is not a static function,
> having more sanity checks could help prevent the unexpected results.

If that's the case then imsic_get_data() should return NULL if
imsic_ptr_offset == 0

Regards,
Anup

>
> Regards,
> Cyan
>
> > >
> > > Signed-off-by: Cyan Yang <cyan.yang at sifive.com>
> > > ---
> > >  lib/utils/irqchip/imsic.c | 7 ++++++-
> > >  1 file changed, 6 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/lib/utils/irqchip/imsic.c b/lib/utils/irqchip/imsic.c
> > > index f2a35c6..e6a3657 100644
> > > --- a/lib/utils/irqchip/imsic.c
> > > +++ b/lib/utils/irqchip/imsic.c
> > > @@ -243,10 +243,15 @@ void imsic_local_irqchip_init(void)
> > >
> > >  int imsic_warm_irqchip_init(void)
> > >  {
> > > +       int rc;
> > >         struct imsic_data *imsic = imsic_get_data(current_hartid());
> > >
> > >         /* Sanity checks */
> > > -       if (!imsic || !imsic->targets_mmode)
> > > +       rc = imsic_data_check(imsic);
> > > +       if (rc)
> > > +               return rc;
> > > +
> > > +       if (!imsic->targets_mmode)
> > >                 return SBI_EINVAL;
> > >
> > >         /* Disable all interrupts */
> > > --
> > > 2.39.3 (Apple Git-146)
> > >
> > >
> > > --
> > > opensbi mailing list
> > > opensbi at lists.infradead.org
> > > http://lists.infradead.org/mailman/listinfo/opensbi
> >
> > Regards,
> > Anup