Re: [PATCH] of: Check for phys_addr_t overflows in early_init_dt_add_memory_arch

[Nicolas Pitre <nicolas.pitre@linaro.org>]

On Thu, 19 Jun 2014, Rob Herring wrote:

> On Thu, Jun 19, 2014 at 12:04 AM, Laura Abbott <lauraa@codeaurora.org> wrote:
> > The common early_init_dt_add_memory_arch takes the base and size
> > of a memory region as u64 types. The function never checks if
> > the base and size can actually fit in a phys_addr_t which may
> > be smaller than 64-bits. This may result in incorrect memory
> > being passed to memblock_add if the memory falls outside the
> > range of phys_addr_t. Add range checks for the base and size if
> > phys_addr_t is smaller than u64.
> >
> > Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
> > Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
> > ---
> > Geert, can you drop my other patch and give this a test to see if it fixes
> > your bootup problem?
> >
> > ---
> >  drivers/of/fdt.c | 15 +++++++++++++++
> >  1 file changed, 15 insertions(+)
> >
> > diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> > index c4cddf0..f72132c 100644
> > --- a/drivers/of/fdt.c
> > +++ b/drivers/of/fdt.c
> > @@ -880,6 +880,21 @@ void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
> >         const u64 phys_offset = __pa(PAGE_OFFSET);
> >         base &= PAGE_MASK;
> >         size &= PAGE_MASK;
> > +
> > +#ifndef CONFIG_ARCH_PHYS_ADDR_T_64BIT
> > +       if (base > ULONG_MAX) {
> 
> How about removing the ifdef and doing something like:
> 
> if ((base >> 32) && (sizeof(phys_addr_t) != sizeof(u64)))

That is what I was about to suggest as well.  Except that I'd use 
sizeof(phys_addr_t) < sizeof(u64) just in case.


Nicolas