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

[Rob Herring]

On Thu, Jun 19, 2014 at 12:04 AM, Laura Abbott <lauraa@xxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxx>
> Signed-off-by: Laura Abbott <lauraa@xxxxxxxxxxxxxx>
> ---
> 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)))

> +               pr_warning("Ignoring memory block 0x%llx - 0x%llx\n",
> +                               base, base + size);
> +               return;
> +       }
> +
> +       if (base + size > ULONG_MAX) {
> +               pr_warning("Ignoring memory range 0x%lx - 0x%llx\n",
> +                               ULONG_MAX, base + size);
> +               size = ULONG_MAX - base;
> +       }
> +#endif
> +
>         if (base + size < phys_offset) {
>                 pr_warning("Ignoring memory block 0x%llx - 0x%llx\n",
>                            base, base + size);
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> hosted by The Linux Foundation
>
>
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