Re: [Xen-devel] Ping: [PATCH] VT-d: protect against bogus information coming from BIOS

[Ben Guthro <ben@xxxxxxxxxx>]

On Mon, Aug 5, 2013 at 9:06 AM, Jan Beulich <JBeulich@xxxxxxxx> wrote:

Ping?

>>> On 10.07.13 at 12:26, "Jan Beulich" <JBeulich@xxxxxxxx> wrote:
> Add checks similar to those done by Linux: The DRHD address must not
> be all zeros or all ones (Linux only checks for zero), and capabilities
> as well as extended capabilities must not be all ones.
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>

Looks OK to me, FWIW

You can add

Reviewed-by: Ben Guthro <benjamin.guthro@xxxxxxxxxx>

 

> --- a/xen/drivers/passthrough/vtd/dmar.c
> +++ b/xen/drivers/passthrough/vtd/dmar.c
> @@ -447,6 +447,9 @@ acpi_parse_one_drhd(struct acpi_dmar_hea
>      if ( (ret = acpi_dmar_check_length(header, sizeof(*drhd))) != 0 )
>          return ret;
>
> +    if ( !drhd->address || !(drhd->address + 1) )
> +        return -ENODEV;
> +
>      dmaru = xzalloc(struct acpi_drhd_unit);
>      if ( !dmaru )
>          return -ENOMEM;
> --- a/xen/drivers/passthrough/vtd/iommu.c
> +++ b/xen/drivers/passthrough/vtd/iommu.c
> @@ -1159,6 +1159,9 @@ int __init iommu_alloc(struct acpi_drhd_
>          dprintk(VTDPREFIX,
>                  "cap = %"PRIx64" ecap = %"PRIx64"\n", iommu->cap, iommu->ecap);
>      }
> +    if ( !(iommu->cap + 1) || !(iommu->ecap + 1) )
> +        return -ENODEV;
> +
>      if ( cap_fault_reg_offset(iommu->cap) +
>           cap_num_fault_regs(iommu->cap) * PRIMARY_FAULT_REG_LEN >= PAGE_SIZE
> ||
>           ecap_iotlb_offset(iommu->ecap) >= PAGE_SIZE )

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