Currently, you can give no encryption format for a qcow file while still
passing a key-secret.  That does not conform to the schema, so this
patch changes the schema to allow it.

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 qapi/block-core.json | 28 +++++++++++++++++++++++++---
 1 file changed, 25 insertions(+), 3 deletions(-)

diff --git a/qapi/block-core.json b/qapi/block-core.json
index 092a1aba2d..d98af0a71d 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2712,15 +2712,35 @@
   'data': { 'flags': 'Qcow2OverlapCheckFlags',
             'mode':  'Qcow2OverlapCheckMode' } }
 
+##
+# @BlockdevQcowEncryptionSecret:
+#
+# Allows specifying a key-secret without specifying the exact
+# encryption format, which is determined automatically from the image
+# header.
+#
+# @key-secret:      The ID of a QCryptoSecret object providing the
+#                   decryption key.  Mandatory except when probing
+#                   image for metadata only.
+#
+# Since: 2.13
+##
+{ 'struct': 'BlockdevQcowEncryptionSecret',
+  'data': { '*key-secret': 'str' } }
+
 ##
 # @BlockdevQcowEncryptionFormat:
 #
 # @aes: AES-CBC with plain64 initialization vectors
 #
+# @from-image:      Determine the encryption format from the image
+#                   header.  This only allows the use of the
+#                   key-secret option.  (Since: 2.13)
+#
 # Since: 2.10
 ##
 { 'enum': 'BlockdevQcowEncryptionFormat',
-  'data': [ 'aes' ] }
+  'data': [ 'aes', 'from-image' ] }
 
 ##
 # @BlockdevQcowEncryption:
@@ -2728,9 +2748,11 @@
 # Since: 2.10
 ##
 { 'union': 'BlockdevQcowEncryption',
-  'base': { 'format': 'BlockdevQcowEncryptionFormat' },
+  'base': { '*format': 'BlockdevQcowEncryptionFormat' },
   'discriminator': 'format',
-  'data': { 'aes': 'QCryptoBlockOptionsQCow' } }
+  'default-variant': 'from-image',
+  'data': { 'aes': 'QCryptoBlockOptionsQCow',
+            'from-image': 'BlockdevQcowEncryptionSecret' } }
 
 ##
 # @BlockdevOptionsQcow:
-- 
2.14.3

On 05/09/2018 11:55 AM, Max Reitz wrote:
> Currently, you can give no encryption format for a qcow file while still
> passing a key-secret.  That does not conform to the schema, so this
> patch changes the schema to allow it.
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---

>   ##
>   # @BlockdevQcowEncryptionFormat:
>   #
>   # @aes: AES-CBC with plain64 initialization vectors
>   #
> +# @from-image:      Determine the encryption format from the image
> +#                   header.  This only allows the use of the
> +#                   key-secret option.  (Since: 2.13)
> +#
>   # Since: 2.10
>   ##
>   { 'enum': 'BlockdevQcowEncryptionFormat',
> -  'data': [ 'aes' ] }
> +  'data': [ 'aes', 'from-image' ] }

Overkill.  Why not just:

>   
>   ##
>   # @BlockdevQcowEncryption:
> @@ -2728,9 +2748,11 @@
>   # Since: 2.10
>   ##
>   { 'union': 'BlockdevQcowEncryption',
> -  'base': { 'format': 'BlockdevQcowEncryptionFormat' },
> +  'base': { '*format': 'BlockdevQcowEncryptionFormat' },
>     'discriminator': 'format',
> -  'data': { 'aes': 'QCryptoBlockOptionsQCow' } }
> +  'default-variant': 'from-image',

'default-variant': 'aes'

> +  'data': { 'aes': 'QCryptoBlockOptionsQCow',

and call it good, because there are no other options to pick from, so 
'from-image' would always resolve to 'aes' anyway.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

On Thu, May 10, 2018 at 09:24:24AM -0500, Eric Blake wrote:
> On 05/09/2018 11:55 AM, Max Reitz wrote:
> > Currently, you can give no encryption format for a qcow file while still
> > passing a key-secret.  That does not conform to the schema, so this
> > patch changes the schema to allow it.
> > 
> > Signed-off-by: Max Reitz <mreitz@redhat.com>
> > ---
> 
> >   ##
> >   # @BlockdevQcowEncryptionFormat:
> >   #
> >   # @aes: AES-CBC with plain64 initialization vectors
> >   #
> > +# @from-image:      Determine the encryption format from the image
> > +#                   header.  This only allows the use of the
> > +#                   key-secret option.  (Since: 2.13)
> > +#
> >   # Since: 2.10
> >   ##
> >   { 'enum': 'BlockdevQcowEncryptionFormat',
> > -  'data': [ 'aes' ] }
> > +  'data': [ 'aes', 'from-image' ] }
> 
> Overkill.  Why not just:
> 
> >   ##
> >   # @BlockdevQcowEncryption:
> > @@ -2728,9 +2748,11 @@
> >   # Since: 2.10
> >   ##
> >   { 'union': 'BlockdevQcowEncryption',
> > -  'base': { 'format': 'BlockdevQcowEncryptionFormat' },
> > +  'base': { '*format': 'BlockdevQcowEncryptionFormat' },
> >     'discriminator': 'format',
> > -  'data': { 'aes': 'QCryptoBlockOptionsQCow' } }
> > +  'default-variant': 'from-image',
> 
> 'default-variant': 'aes'
> 
> > +  'data': { 'aes': 'QCryptoBlockOptionsQCow',
> 
> and call it good, because there are no other options to pick from, so
> 'from-image' would always resolve to 'aes' anyway.

Sounds reasonable because qcowv1 is a dead format we don't intend to
add more features to.


Regards,
Daniel
-- 
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On 2018-05-10 16:24, Eric Blake wrote:
> On 05/09/2018 11:55 AM, Max Reitz wrote:
>> Currently, you can give no encryption format for a qcow file while still
>> passing a key-secret.  That does not conform to the schema, so this
>> patch changes the schema to allow it.
>>
>> Signed-off-by: Max Reitz <mreitz@redhat.com>
>> ---
> 
>>   ##
>>   # @BlockdevQcowEncryptionFormat:
>>   #
>>   # @aes: AES-CBC with plain64 initialization vectors
>>   #
>> +# @from-image:      Determine the encryption format from the image
>> +#                   header.  This only allows the use of the
>> +#                   key-secret option.  (Since: 2.13)
>> +#
>>   # Since: 2.10
>>   ##
>>   { 'enum': 'BlockdevQcowEncryptionFormat',
>> -  'data': [ 'aes' ] }
>> +  'data': [ 'aes', 'from-image' ] }
> 
> Overkill.  Why not just:
> 
>>     ##
>>   # @BlockdevQcowEncryption:
>> @@ -2728,9 +2748,11 @@
>>   # Since: 2.10
>>   ##
>>   { 'union': 'BlockdevQcowEncryption',
>> -  'base': { 'format': 'BlockdevQcowEncryptionFormat' },
>> +  'base': { '*format': 'BlockdevQcowEncryptionFormat' },
>>     'discriminator': 'format',
>> -  'data': { 'aes': 'QCryptoBlockOptionsQCow' } }
>> +  'default-variant': 'from-image',
> 
> 'default-variant': 'aes'
> 
>> +  'data': { 'aes': 'QCryptoBlockOptionsQCow',
> 
> and call it good, because there are no other options to pick from, so
> 'from-image' would always resolve to 'aes' anyway.

Hmmmm.  Yes. :-)

Max