[libvirt] [PATCH v2 4/4] security: don't relabel chardev source if virtlogd is used as stdio handler

[Martin Kletzander]

On Thu, Jun 15, 2017 at 10:12:51PM -0400, John Ferlan wrote:
>On 06/15/2017 10:40 AM, Pavel Hrdina wrote:
>> On Thu, Jun 15, 2017 at 07:57:18AM -0400, John Ferlan wrote:
>>> On 06/15/2017 03:11 AM, Pavel Hrdina wrote:
>>>> On Tue, Jun 13, 2017 at 08:00:41PM -0400, John Ferlan wrote:

[...]

>>>>> Wouldn't these changes end up selecting "any" chardev if
>>>>> chardevStdioLogd ended up being set regardless of whether they were
>>>>> actually using the log file?
>>>>
>>>> I don't know what you mean by this sentence?
>>>>
>>>
>>> Well let's see, chardevStdioLogd is set to true when meeting the two
>>> conditions a qemu.conf global "cfg->stdioLogd" && a per domain or
>>> emulator image capability "QEMU_CAPS_CHARDEV_FILE_APPEND".
>>>
>>> So, conceivably chardevStdioLogd could be true for *any* domain as long
>>> as those conditions are met, right?
>>
>> Yes, the two conditions are checked while starting a new domain in
>> qemuProcessPrepareDomain() and stored in the private date of that
>> domain.
>>
>>> If you have a domain that has chardev's which are not configured to use
>>> the stdio handler, then the chardevStdioLogd could still be true, right?
>>
>> No, if the @chardevStdioLogd is true all char devices for that domain
>> will use virtlogd.
>>
>
>This is the part I'm stuck on as to why - based on the previous
>assertion. I'm just not visualizing all those various chardev configs.
>Just so you know - I have to be out Friday, but will be back Monday. If
>you get someone else to ACK this one in the mean time - that's fine.
>

The usage of virlogd can be only set in qemu.conf, not per-chardev, not
even per-domain.  We need to save it per-domain, though, as it can
differ for domains started before and after that setting was changed in
qemu.conf and the daemon restarted (or updated to a version with support
for virtlogd as that is the default if nothing is specified in the
config).

The hotplug should be fixed, but as you said that can be a follow-up patch.

Reviewed-by: Martin Kletzander <mkletzan at redhat.com>
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