[libvirt] [PATCH 10/13] qemu: Add TLS params to _qemuMonitorMigrationParams

[John Ferlan]

On 02/21/2017 04:53 PM, Jiri Denemark wrote:
> On Tue, Feb 21, 2017 at 22:06:02 +0100, Jiri Denemark wrote:
>> On Fri, Feb 17, 2017 at 14:39:27 -0500, John Ferlan wrote:
>>> Add the fields to support setting tls-creds and tls-hostname during
>>> a migration (either source or target)
>>>
>>> Signed-off-by: John Ferlan <jferlan at redhat.com>
>>> ---
>>>  src/qemu/qemu_monitor.c      | 12 +++++++++---
>>>  src/qemu/qemu_monitor.h      |  7 +++++++
>>>  src/qemu/qemu_monitor_json.c | 11 +++++++++++
>>>  3 files changed, 27 insertions(+), 3 deletions(-)
>> ...
>>> diff --git a/src/qemu/qemu_monitor.h b/src/qemu/qemu_monitor.h
>>> index 8811d85..d719112 100644
>>> --- a/src/qemu/qemu_monitor.h
>>> +++ b/src/qemu/qemu_monitor.h
>>> @@ -570,6 +570,13 @@ struct _qemuMonitorMigrationParams {
>>>  
>>>      bool cpuThrottleIncrement_set;
>>>      int cpuThrottleIncrement;
>>> +
>>> +    /* Input only for destination */
>>
>> What do you mean by this comment? I think you can just safely drop it
>> :-)
>>

Hmm it was only a couple days ago and I cannot recall...

>>> +    bool migrateTLSAlias_set;
>>> +    char *migrateTLSAlias;
>>> +
>>> +    bool migrateTLSHostname_set;
>>> +    char *migrateTLSHostname;
>>
>> Both parameters are set-only, we never read them back from QEMU so
>> there's no need for the *_set booleans. Especially when NULL tells that
>> pretty clearly.
>>
>>>  };
>>>  
>>>  int qemuMonitorGetMigrationParams(qemuMonitorPtr mon,
>>> diff --git a/src/qemu/qemu_monitor_json.c b/src/qemu/qemu_monitor_json.c
>>> index 7aa9e31..7a70366 100644
>>> --- a/src/qemu/qemu_monitor_json.c
>>> +++ b/src/qemu/qemu_monitor_json.c
>>> @@ -2637,6 +2637,17 @@ qemuMonitorJSONSetMigrationParams(qemuMonitorPtr mon,
>>>  
>>>  #undef APPEND
>>>  
>>> +    /* Set only parameters for TLS migration options */
>>
>> Looks like another useless comment.
>>
>>> +    if (params->migrateTLSAlias_set &&
>>> +        virJSONValueObjectAppendString(args, "tls-creds",
>>> +                                       params->migrateTLSAlias) < 0)
>>> +        goto cleanup;
>>> +
>>> +    if (params->migrateTLSHostname_set &&
>>> +        virJSONValueObjectAppendString(args, "tls-hostname",
>>> +                                       params->migrateTLSHostname) < 0)
>>> +        goto cleanup;
> 
> And we should always set these parameters if QEMU supports them to make
> sure some stale values are not used when VIR_MIGRATE_TLS is not set. So
> we might actually need the *_set booleans, but it depends on the way we
> implement the logic to reset the parameters. Which brings a question...
> how do we reset these parameters?

tls-hostname is only set on the client and only under certain
circumstances.  As for reset, I guess I assumed (hah!) deletion of the
objects after the migration was done would cause the parameters to
magically go away too.

FWIW: Trying to follow the logic from:

https://www.berrange.com/posts/2016/08/16/improving-qemu-security-part-7-tls-support-for-migration/


John