Re: [Xen-devel] Problem with using Libvmi or xenaccess with xen

[Steven Maresca <steve@xxxxxxxxxxxx>]

On Mon, Jul 8, 2013 at 9:25 AM, Mina Jafari <ai.minajafari@xxxxxxxxx> wrote:

Hi all,
Can dom0 have enough privilege to access domu's kernel memory using Libvmi functions?

Libvmi use xenaccess functions in fact, and as it is a user space library I'm asking this.

I wanna read system call table of domu through dom0.

Thanks

 

Mina,

Use of LibVMI in this manner should provide the basic foundational components that you require: Domain 0 has implicit privilege to access domU memory as a consequence of being the privileged management domain, and LibVMI operations from dom0 should work without changes to your Xen configuration. I would recommend that you begin observation in dom0 as a path of least resistance.

It is possible to use LibVMI within a domU to examine other domUs, but only via a XSM policy. Such a policy must grant to the observing domU ability to invoke a variety of privileged operations upon the target domU.  This is really only viable with Xen 4.3 and a recent kernel in the observing domU -- the XSM wiki page has more information.

Always keep in mind that you are inspecting untrusted, potentially malicious memory; be very cautious with the data LibVMI provides.

Steve

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