Re: [Xen-devel] Device model operation hypercall (DMOP, re qemu depriv)

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 15.08.16 at 12:47, <george.dunlap@xxxxxxxxxx> wrote:
> On 15/08/16 11:19, Jan Beulich wrote:
>> Well, none of the options considered so far are really nice or
>> readily available. I think the easiest to use for both the caller and
>> the implementation of the hypercall would be the auxiliary
>> hypercall for a kernel to indicate user/kernel boundaries plus a
>> flag on the DMOP one for the kernel mode driver to indicate its
>> user mode origin. The main (purely theoretical afaict) downside
>> of this is the difficulty to use it in OSes with variable user/kernel
>> boundaries.
> 
> What about including in the "fixed" part of the hypercall a virtual
> address range that all pointers must be in?  That wouldn't even require
> a user/kernel flag actually; and could conceivably be used by the caller
> (either userspace or kernel space) to thwart certain kinds of potential
> attacks.

That's definitely an option, if we're sufficiently certain that no OSes
will ever require two or more ranges.

Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel