From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrii Tseglytskyi <andrii.tseglytskyi@globallogic.com>
Subject: Re: [PATCH v02 6/7] arm: introduce
	do_translate_pagetable hypercall
Date: Tue, 22 Jul 2014 19:39:09 +0300
Message-ID: <CAH_mUMNEyAvniHG7aoQR2NRVBOOfJLtXMF-ZxZnzTCKDTygZyw@mail.gmail.com>
References: <1403780826-22123-1-git-send-email-andrii.tseglytskyi@globallogic.com>
	<1403780826-22123-7-git-send-email-andrii.tseglytskyi@globallogic.com>
	<53B6BB99.7060107@linaro.org>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Return-path: <xen-devel-bounces@lists.xen.org>
In-Reply-To: <53B6BB99.7060107@linaro.org>
List-Unsubscribe: <http://lists.xen.org/cgi-bin/mailman/options/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xen.org>
List-Help: <mailto:xen-devel-request@lists.xen.org?subject=help>
List-Subscribe: <http://lists.xen.org/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=subscribe>
Sender: xen-devel-bounces@lists.xen.org
Errors-To: xen-devel-bounces@lists.xen.org
To: Julien Grall <julien.grall@linaro.org>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Ian Campbell <Ian.Campbell@citrix.com>, xen-devel@lists.xen.org
List-Id: xen-devel@lists.xenproject.org

Hi Julien,

On Fri, Jul 4, 2014 at 5:35 PM, Julien Grall <julien.grall@linaro.org> wrote:
> Hi Andrii,
>
>
> On 26/06/14 12:07, Andrii Tseglytskyi wrote:
>>
>> +long do_translate_pagetable(int cmd,
>> XEN_GUEST_HANDLE_PARAM(xen_pagetable_addr_t) pgt_addr)
>> +{
>> +    struct xen_pagetable_addr pgt;
>> +    struct mmu_info *mmu = NULL;
>> +
>> +    if ( copy_from_guest(&pgt, pgt_addr, 1) )
>> +        return -EFAULT;
>> +
>> +    mmu = mmu_lookup(pgt.reg);
>> +    if ( !mmu )
>> +    {
>> +        pr_mmu("can't get mmu for addr 0x%08x", pgt.reg);
>> +        return -EINVAL;
>> +    }
>> +
>> +    pgt.maddr = mmu_translate_pagetable(mmu, pgt.paddr);
>> +
>> +    return copy_to_guest(pgt_addr, &pgt, 1);
>> +}
>> +
>
>
> AFAIU, nothing prevents a malicious guest to call this hypercall and screw
> the pagetable of the MMU.

Right. Do you think that some kind of security checks needed here?


>
> Regards,
>
> --
> Julien Grall



-- 

Andrii Tseglytskyi | Embedded Dev
GlobalLogic
www.globallogic.com