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From: "Daniel P. Berrangé" <berrange@redhat.com>
To: Max Reitz <mreitz@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Fam Zheng <fam@euphon.net>,
	qemu-block@nongnu.org, Markus Armbruster <armbru@redhat.com>,
	qemu-devel@nongnu.org, Maxim Levitsky <mlevitsk@redhat.com>,
	Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 07/13] block: add manage-encryption command (qmp and blockdev)
Date: Thu, 22 Aug 2019 12:14:09 +0100
Message-ID: <20190822111409.GM3267@redhat.com> (raw)
In-Reply-To: <12c342c8-6ac8-3533-7a7b-e61826e9abb0@redhat.com>

On Tue, Aug 20, 2019 at 08:27:48PM +0200, Max Reitz wrote:
> On 14.08.19 22:22, Maxim Levitsky wrote:
> > This adds:
> > 
> > * x-blockdev-update-encryption and x-blockdev-erase-encryption qmp commands
> >   Both commands take the QCryptoKeyManageOptions
> >   the x-blockdev-update-encryption is meant for non destructive addition
> >   of key slots / whatever the encryption driver supports in the future
> > 
> >   x-blockdev-erase-encryption is meant for destructive encryption key erase,
> >   in some cases even without way to recover the data.
> > 
> > 
> > * bdrv_setup_encryption callback in the block driver
> >   This callback does both the above functions with 'action' parameter
> > 
> > * QCryptoKeyManageOptions with set of options that drivers can use for encryption managment
> >   Currently it has all the options that LUKS needs, and later it can be extended
> >   (via union) to support more encryption drivers if needed
> > 
> > * blk_setup_encryption / bdrv_setup_encryption - the usual block layer wrappers.
> >   Note that bdrv_setup_encryption takes BlockDriverState and not BdrvChild,
> >   for the ease of use from the qmp code. It is not expected that this function
> >   will be used by anything but qmp and qemu-img code
> > 
> > 
> > Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
> > ---
> >  block/block-backend.c          |  9 ++++++++
> >  block/io.c                     | 24 ++++++++++++++++++++
> >  blockdev.c                     | 40 ++++++++++++++++++++++++++++++++++
> >  include/block/block.h          | 12 ++++++++++
> >  include/block/block_int.h      | 11 ++++++++++
> >  include/sysemu/block-backend.h |  7 ++++++
> >  qapi/block-core.json           | 36 ++++++++++++++++++++++++++++++
> >  qapi/crypto.json               | 26 ++++++++++++++++++++++
> >  8 files changed, 165 insertions(+)
> 
> Now I don’t know whether you want to keep this interface at all, because
> the cover letter seemed to imply you’d prefer a QMP amend.  But let it
> be said that a QMP amend is no trivial task.  I think the most difficult
> bit is that the qcow2 implementation currently is inherently an offline
> operation.  It isn’t a good idea to use it on a live image.  (Maybe it
> works, but it’s definitely not what I had in mind when I wrote it.)

For key mgmt we definitely need to have an online capability.

If layering it into a general purpose format "amend' option
is too complex, then we should keep it separate rather than
making our lives uncecessarily difficult IMHO.

> > diff --git a/qapi/block-core.json b/qapi/block-core.json
> > index 0d43d4f37c..53ed411eed 100644
> > --- a/qapi/block-core.json
> > +++ b/qapi/block-core.json
> > @@ -5327,3 +5327,39 @@
> >    'data' : { 'node-name': 'str',
> >               'iothread': 'StrOrNull',
> >               '*force': 'bool' } }
> > +
> > +
> > +##
> > +# @x-blockdev-update-encryption:
> > +#
> > +# Update the encryption keys for an encrypted block device
> > +#
> > +# @node-name: 	  Name of the blockdev to operate on
> > +# @force:         Disable safety checks (use with care)
> > +# @options:       Driver specific options
> > +#
> > +
> > +# Since: 4.2
> > +##
> > +{ 'command': 'x-blockdev-update-encryption',
> > +  'data': { 'node-name' : 'str',
> > +            '*force' : 'bool',
> > +            'options': 'QCryptoEncryptionSetupOptions' } }
> > +
> > +##
> > +# @x-blockdev-erase-encryption:
> > +#
> > +# Erase the encryption keys for an encrypted block device
> > +#
> > +# @node-name: 	  Name of the blockdev to operate on
> 
> Why the tab?
> 
> > +# @force:         Disable safety checks (use with care)
> 
> I think being a bit more verbose wouldn’t hurt.
> 
> (Same above.)
> 
> > +# @options:       Driver specific options
> > +#
> > +# Returns: @QCryptoKeyManageResult
> > +#
> > +# Since: 4.2
> > +##
> > +{ 'command': 'x-blockdev-erase-encryption',
> > +  'data': { 'node-name' : 'str',
> > +            '*force' : 'bool',
> > +            'options': 'QCryptoEncryptionSetupOptions' } }
> > diff --git a/qapi/crypto.json b/qapi/crypto.json
> > index b2a4cff683..69e8b086db 100644
> > --- a/qapi/crypto.json
> > +++ b/qapi/crypto.json
> > @@ -309,3 +309,29 @@
> >    'base': 'QCryptoBlockInfoBase',
> >    'discriminator': 'format',
> >    'data': { 'luks': 'QCryptoBlockInfoLUKS' } }
> > +
> > +
> > +##
> > +# @QCryptoEncryptionSetupOptions:
> > +#
> > +# Driver specific options for encryption key management.
> 
> The options do seem LUKS-specific, but the name of this structure does not.
> 
> > +# @key-secret: the ID of a QCryptoSecret object providing the password
> > +#              to add or to erase (optional for erase)
> > +#
> > +# @old-key-secret: the ID of a QCryptoSecret object providing the password
> > +#                  that can currently unlock the image
> > +#
> > +# @slot: Key slot to update/erase
> > +#        (optional, for update will select a free slot,
> > +#        for erase will erase all slots that match the password)
> > +#
> > +# @iter-time: number of milliseconds to spend in
> > +#             PBKDF passphrase processing. Currently defaults to 2000
> > +# Since: 4.2
> > +##
> 
> Does it really make sense to use the same structure for erasing and
> updating?  I think there are ways to represent @key-secret vs. @slot
> being alternatives to each other for erase; @iter-time doesn’t seem to
> make sense for erase; and @slot doesn’t seem to make sense for update.
> Also, I don’t know whether to use @key-secret or @old-key-secret for erase.
> 
> All in all, it seems more sensible to me to have separate structs for
> updating and erasing.

I agree, we can get a more understandable schema if each
command has its own struct wit the right options.

Regards,
Daniel
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  parent reply index

Thread overview: 87+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-14 20:22 [Qemu-devel] [PATCH 00/13] RFC: luks/encrypted qcow2 key management Maxim Levitsky
2019-08-14 20:22 ` [Qemu-devel] [PATCH 01/13] block-crypto: misc refactoring Maxim Levitsky
2019-08-20 16:38   ` Max Reitz
2019-08-22  0:05     ` Maxim Levitsky
2019-08-22 14:34       ` Max Reitz
2019-08-22 15:04         ` Maxim Levitsky
2019-08-21 15:39   ` Daniel P. Berrangé
2019-08-22  0:08     ` Maxim Levitsky
2019-08-14 20:22 ` [Qemu-devel] [PATCH 02/13] qcrypto-luks: " Maxim Levitsky
2019-08-15 21:40   ` [Qemu-devel] [Qemu-block] " John Snow
2019-08-19 14:21     ` Maxim Levitsky
2019-08-22 10:29     ` Daniel P. Berrangé
2019-08-22 11:04       ` Maxim Levitsky
2019-08-22 11:10         ` Daniel P. Berrangé
2019-08-22 11:13           ` Maxim Levitsky
2019-08-20 17:36   ` [Qemu-devel] " Max Reitz
2019-08-21 23:59     ` Maxim Levitsky
2019-08-22 14:32       ` Max Reitz
2019-08-25 10:46         ` Maxim Levitsky
2019-08-14 20:22 ` [Qemu-devel] [PATCH 03/13] qcrypto-luks: refactoring: extract load/store/check/parse header functions Maxim Levitsky
2019-08-20 18:01   ` Max Reitz
2019-08-21 22:43     ` Maxim Levitsky
2019-08-22 10:32       ` Daniel P. Berrangé
2019-08-22 10:57         ` Maxim Levitsky
2019-08-22 10:34       ` Daniel P. Berrangé
2019-08-25 14:11         ` Maxim Levitsky
2019-08-22 10:38   ` Daniel P. Berrangé
2019-08-25 14:09     ` Maxim Levitsky
2019-08-14 20:22 ` [Qemu-devel] [PATCH 04/13] qcrypto-luks: refactoring: simplify the math used for keyslot locations Maxim Levitsky
2019-08-22 10:47   ` Daniel P. Berrangé
2019-08-25 14:30     ` Maxim Levitsky
2019-08-14 20:22 ` [Qemu-devel] [PATCH 05/13] qcrypto-luks: clear the masterkey and password before freeing them always Maxim Levitsky
2019-08-20 18:12   ` Max Reitz
2019-08-21 22:40     ` Maxim Levitsky
2019-08-22 10:49     ` Daniel P. Berrangé
2019-08-22 10:56       ` Maxim Levitsky
2019-08-25 15:31         ` Maxim Levitsky
2019-08-25 17:15           ` Maxim Levitsky
2019-08-27  8:55           ` Daniel P. Berrangé
2019-08-21 23:01   ` [Qemu-devel] [Qemu-block] " Nir Soffer
2019-08-21 23:11     ` Maxim Levitsky
2019-08-14 20:22 ` [Qemu-devel] [PATCH 06/13] qcrypto-luks: implement more rigorous header checking Maxim Levitsky
2019-08-22 11:04   ` Daniel P. Berrangé
2019-08-25 15:40     ` Maxim Levitsky
2019-08-25 16:08       ` Maxim Levitsky
2019-08-26 13:31         ` Eric Blake
2019-08-26 13:39           ` Maxim Levitsky
2019-08-27  8:56         ` Daniel P. Berrangé
2019-08-14 20:22 ` [Qemu-devel] [PATCH 07/13] block: add manage-encryption command (qmp and blockdev) Maxim Levitsky
2019-08-20 18:27   ` Max Reitz
2019-08-21 22:32     ` Maxim Levitsky
2019-08-22 11:14     ` Daniel P. Berrangé [this message]
2019-08-21 11:47   ` Markus Armbruster
2019-08-21 22:24     ` Maxim Levitsky
2019-08-22 14:07       ` Markus Armbruster
2019-08-25 16:42         ` Maxim Levitsky
2019-08-14 20:22 ` [Qemu-devel] [PATCH 08/13] qcrypto: add the plumbing for encryption management Maxim Levitsky
2019-08-22 11:16   ` Daniel P. Berrangé
2019-08-22 11:47     ` Maxim Levitsky
2019-08-22 11:49       ` Daniel P. Berrangé
2019-08-14 20:22 ` [Qemu-devel] [PATCH 09/13] qcrypto-luks: implement the encryption key management Maxim Levitsky
2019-08-22 11:27   ` Daniel P. Berrangé
2019-08-25 17:01     ` Maxim Levitsky
2019-08-14 20:22 ` [Qemu-devel] [PATCH 10/13] block/crypto: " Maxim Levitsky
2019-08-22 11:29   ` Daniel P. Berrangé
2019-08-22 11:36     ` Maxim Levitsky
2019-08-14 20:22 ` [Qemu-devel] [PATCH 11/13] block/qcow2: implement the encryption key managment Maxim Levitsky
2019-08-14 20:22 ` [Qemu-devel] [PATCH 12/13] qemu-img: implement key management Maxim Levitsky
2019-08-20 18:29   ` Max Reitz
2019-08-21 22:33     ` Maxim Levitsky
2019-08-22 11:32     ` Daniel P. Berrangé
2019-08-22 14:42       ` Max Reitz
2019-08-25 17:04         ` Maxim Levitsky
2019-08-14 20:22 ` [Qemu-devel] [PATCH 13/13] iotests : add tests for encryption " Maxim Levitsky
2019-08-14 21:08 ` [Qemu-devel] [PATCH 00/13] RFC: luks/encrypted qcow2 " Eric Blake
2019-08-15  8:49   ` Maxim Levitsky
2019-08-15  9:10   ` Kevin Wolf
2019-08-15 14:18     ` Markus Armbruster
2019-08-15 14:44       ` Maxim Levitsky
2019-08-15 15:00         ` Eric Blake
2019-08-19 12:35           ` Maxim Levitsky
2019-08-21 11:31             ` Markus Armbruster
2019-08-21 13:22               ` Maxim Levitsky
2019-08-20 17:59 ` Max Reitz
2019-08-21 22:00   ` Maxim Levitsky
2019-08-22 11:35 ` Daniel P. Berrangé
2019-08-25 17:10   ` Maxim Levitsky

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