Mailing List Archive: [PATCH] x86: properly check XEN_DOMCTL_ioport

In particular, the case of "np" being a very large value wasn't handled
correctly. The range start checks also were off by one (except that in
practice, when "np" is properly range checked, this would still have
been caught by the range end checks).

Also, is a GFN wrap in XEN_DOMCTL_memory_mapping really okay?

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -884,7 +884,7 @@ long arch_do_domctl(
int found = 0;

ret = -EINVAL;
- if ( (np == 0) || (fgp > MAX_IOPORTS) || (fmp > MAX_IOPORTS) ||
+ if ( ((fgp | fmp | (np - 1)) >= MAX_IOPORTS) ||
((fgp + np) > MAX_IOPORTS) || ((fmp + np) > MAX_IOPORTS) )
{
printk(XENLOG_G_ERR

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On 18/09/2012 16:24, "Jan Beulich" <JBeulich@suse.com> wrote:

> In particular, the case of "np" being a very large value wasn't handled
> correctly. The range start checks also were off by one (except that in
> practice, when "np" is properly range checked, this would still have
> been caught by the range end checks).
>
> Also, is a GFN wrap in XEN_DOMCTL_memory_mapping really okay?

Probably worth fixing?

> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Acked-by: Keir Fraser <keir@xen.org>

> --- a/xen/arch/x86/domctl.c
> +++ b/xen/arch/x86/domctl.c
> @@ -884,7 +884,7 @@ long arch_do_domctl(
> int found = 0;
>
> ret = -EINVAL;
> - if ( (np == 0) || (fgp > MAX_IOPORTS) || (fmp > MAX_IOPORTS) ||
> + if ( ((fgp | fmp | (np - 1)) >= MAX_IOPORTS) ||
> ((fgp + np) > MAX_IOPORTS) || ((fmp + np) > MAX_IOPORTS) )
> {
> printk(XENLOG_G_ERR
>
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel

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