From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: Keir Fraser <keir@xen.org>,
Ian Campbell <Ian.Campbell@citrix.com>,
Ian Jackson <Ian.Jackson@eu.citrix.com>, Tim Deegan <tim@xen.org>,
Xen-devel <xen-devel@lists.xen.org>
Subject: Re: [Patch v2 3/3] xen/gdbsx: Security audit of {, un}pausevcpu and domstatus hypercalls
Date: Thu, 24 Jul 2014 14:02:43 +0100 [thread overview]
Message-ID: <53D103F3.2010604@citrix.com> (raw)
In-Reply-To: <53D11F0002000078000258A4@mail.emea.novell.com>
On 24/07/14 13:58, Jan Beulich wrote:
>>>> On 24.07.14 at 13:16, <andrew.cooper3@citrix.com> wrote:
>> --- a/xen/arch/x86/domctl.c
>> +++ b/xen/arch/x86/domctl.c
>> @@ -1030,11 +1030,10 @@ long arch_do_domctl(
>> if ( !d->controller_pause_count )
>> break;
>> ret = -EINVAL;
>> - if ( domctl->u.gdbsx_pauseunp_vcpu.vcpu >= MAX_VIRT_CPUS ||
>> + if ( domctl->u.gdbsx_pauseunp_vcpu.vcpu >= d->max_vcpus ||
> As mentioned on IRC - are you sure you can replace (rather than
> amend) the previous bounds check? I.e. do you _know_ that gdbsx
> can deal with guests having more than MAX_VIRT_CPUS vCPU-s?
>
> Jan
>
I have no idea whether it can or not, but if it asks for a legitimate ID
greater than MAX_VIRT_CPUS, then I think it is reasonable to assume yes.
~Andrew
next prev parent reply other threads:[~2014-07-24 13:02 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-24 10:56 [PATCH 0/3] GDBSX fixes Andrew Cooper
2014-07-24 10:56 ` [PATCH 1/3] xen/common: Introduce vcpu_{, un}pause_by_systemcontroller() helpers Andrew Cooper
2014-07-24 10:56 ` [PATCH 2/3] x86/gdbsx: Invert preconditions for XEN_DOMCTL_gdbsx_{, un}pausevcpu hypercalls Andrew Cooper
2014-07-24 10:56 ` [PATCH 3/3] xen/gdbsx: Security audit of {, un}pausevcpu and domstatus hypercalls Andrew Cooper
2014-07-24 11:07 ` Tim Deegan
2014-07-24 11:11 ` Andrew Cooper
2014-07-24 11:16 ` [Patch v2 " Andrew Cooper
2014-07-24 11:41 ` Tim Deegan
2014-07-24 12:58 ` Jan Beulich
2014-07-24 13:02 ` Andrew Cooper [this message]
2014-07-25 1:20 ` Mukesh Rathor
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