[libvirt] [PATCH] qemu: Don't assume secret provided for LUKS encryption

[John Ferlan]

On 01/02/2017 11:20 AM, Ján Tomko wrote:
> On Thu, Dec 22, 2016 at 09:12:43AM -0500, John Ferlan wrote:
>> https://bugzilla.redhat.com/show_bug.cgi?id=1405269
>>
>> If a secret was not provided for what was determined to be a LUKS
>> encrypted disk (during virStorageFileGetMetadata processing when
>> called from qemuDomainDetermineDiskChain as a result of hotplug
>> attach qemuDomainAttachDeviceDiskLive), then do not attempt to
>> look it up (avoiding a libvirtd crash) and do not alter the format
>> to "luks" when adding the disk; otherwise, the device_add would
>> fail with a message such as:
>>
>>   "unable to execute QEMU command 'device_add': Property 'scsi-hd.drive'
>>    can't find value 'drive-scsi0-0-0-0'"
>>
>> because of assumptions that when the format=luks that libvirt would have
>> provided the secret to decrypt the volume.
>>
>> Access to unlock the volume will thus be left to the application.
>>
>> Signed-off-by: John Ferlan <jferlan at redhat.com>
>> ---
>>
>> I could have spread things over 2 patches (one to create the helper
>> and one to add the extra check for nsecrets > 0), but just going with
>> one to fix the issue just felt cleaner (besides makes any possible
>> backports a bit simpler).
>>
>> NB: The "extra" !virStorageSourceIsEmpty check for the qemu_command
>>     path is a no-op essentially.
>>
>> src/qemu/qemu_command.c |  3 +--
>> src/qemu/qemu_domain.c  | 15 +++++++++++++--
>> src/qemu/qemu_domain.h  |  3 +++
>> src/qemu/qemu_hotplug.c |  3 ++-
>> 4 files changed, 19 insertions(+), 5 deletions(-)
>>
> 
> ACK
> 
>> diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
>> index 92a2e73..6b10e63 100644
>> --- a/src/qemu/qemu_hotplug.c
>> +++ b/src/qemu/qemu_hotplug.c
>> @@ -3584,7 +3584,8 @@ qemuDomainRemoveDiskDevice(virQEMUDriverPtr driver,
>>      * can remove the luks object password too
>>      */
>>     if (!virStorageSourceIsEmpty(disk->src) && disk->src->encryption &&
>> -        disk->src->encryption->format ==
>> VIR_STORAGE_ENCRYPTION_FORMAT_LUKS) {
>> +        disk->src->encryption->format ==
>> VIR_STORAGE_ENCRYPTION_FORMAT_LUKS &&
>> +        disk->src->encryption->nsecrets > 0) {
> 
> Why doesn't this code also use the helper?
> 

Strange... Must've quit! rather than written my buffer for hotplug...
who knows - holidays have allowed me to forget ;-)

Modified this path to also use the helper...

Tks -

John