Re: firmware: dmi-sysfs: why is the access mode of dmi sysfs entries restricted to 0400?

[Guoheyi <guoheyi@huawei.com>]

在 2019/12/4 17:29, Greg Kroah-Hartman 写道:
> On Wed, Dec 04, 2019 at 05:01:06PM +0800, Guoheyi wrote:
>> 在 2019/12/4 15:41, Greg Kroah-Hartman 写道:
>>> On Wed, Dec 04, 2019 at 03:31:22PM +0800, Guoheyi wrote:
>>>> Hi,
>>>>
>>>> Why is the access mode of dmi sysfs entries restricted to 0400? Is it for
>>>> security concern? If it is, which information do we consider as privacy?
>>> There's lots of "interesting" information in dmi entries that you
>>> probably do not want all processes reading, which is why they are
>>> restricted.
>>>
>>>> We would like to fetch CPU information from non-root application, is there
>>>> feasible way to do that?
>>> What specific CPU information is not currently exported in /proc/cpuinfo
>>> that only shows up in DMI entries that you are interested in?
>> We'd like to get processor manufacturer, speed and version, and pass the
>> information to qemu virtual machine, for users of VM might be happy to see
>> this instead of "unknown xxx", while qemu may run as non-root.
> Careful about this as if you move that virtual machine around, those
> values will change and if userspace was depending on them being static
> (set up at program start time), then you might have problems.
>
> good luck!

The information will be used as VM DMI/SMBIOS as well, so it will be 
read only once during VM boot. I guess we will be OK :)

Thanks a lot.

Heyi

>
> greg k-h
>
> .