Re: [Xen-devel] [PATCH][cpufreq] add bounds checking for getcpuidletime

[Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>]

This is supposed to be handled by xenctl_cpumap_to_cpumask, but it looks
like it's buggy. I checked in a fix as changeset 16519. Can you please try
with that and see if it fixes your problem?

 -- Keir

On 3/12/07 16:48, "Mark Langsdorf" <mark.langsdorf@xxxxxxx> wrote:

> The Xen platform hypercall for getting the cpu idletime does not
> check to make sure that all cpus in the map have indexes less
> than the size of the array that it writes the data into.  Add
> bounds checking to avoid memory corruption.
> 
> Signed-off-by: Mark Langsdorf <mark.langsdorf@xxxxxxx>
> 
> diff -r d40788f07a4f xen/arch/x86/platform_hypercall.c
> --- a/xen/arch/x86/platform_hypercall.c Sun Nov 25 12:43:13 2007 +0000
> +++ b/xen/arch/x86/platform_hypercall.c Mon Dec 03 10:25:23 2007 -0600
> @@ -326,6 +326,9 @@ ret_t do_platform_op(XEN_GUEST_HANDLE(xe
>                  cpu_clear(cpu, cpumap);
>              }
>  
> +            if (cpu >= ctlmap.nr_cpus)
> +                continue;
> +
>              ret = -EFAULT;
>              if ( copy_to_guest_offset(idletimes, cpu, &idletime, 1) )
>                  goto out;
> 
> 
> 
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> http://lists.xensource.com/xen-devel



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