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From: "Daniel P. Berrangé" <berrange@redhat.com>
To: Maxim Levitsky <mlevitsk@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, Nir Soffer <nsoffer@redhat.com>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Max Reitz <mreitz@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 05/13] qcrypto-luks: clear the masterkey and password before freeing them always
Date: Tue, 27 Aug 2019 09:55:05 +0100
Message-ID: <20190827085505.GC16500@redhat.com> (raw)
In-Reply-To: <cd1bc2cf3e2748db8aa686534ae7d84c71a58e69.camel@redhat.com>

On Sun, Aug 25, 2019 at 06:31:02PM +0300, Maxim Levitsky wrote:
> On Thu, 2019-08-22 at 13:56 +0300, Maxim Levitsky wrote:
> > On Thu, 2019-08-22 at 11:49 +0100, Daniel P. Berrangé wrote:
> > > On Tue, Aug 20, 2019 at 08:12:51PM +0200, Max Reitz wrote:
> > > > On 14.08.19 22:22, Maxim Levitsky wrote:
> > > > > While there are other places where these are still stored in memory,
> > > > > this is still one less key material area that can be sniffed with
> > > > > various side channel attacks
> > > > > 
> > > > > 
> > > > > 
> > > > 
> > > > (Many empty lines here)
> > > > 
> > > > > Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
> > > > > ---
> > > > >  crypto/block-luks.c | 52 ++++++++++++++++++++++++++++++++++++++-------
> > > > >  1 file changed, 44 insertions(+), 8 deletions(-)
> > > > 
> > > > Wouldn’t it make sense to introduce a dedicated function for this?
> > > 
> > > Yes, it would.
> > > 
> > > In fact I have a series pending which bumps min glib and introduces
> > > use of auto-free functions in this code.
> > > 
> > > It would be desirable to have a autp-free func for memset+free
> > > so we can just declare the variable
> > > 
> > >    q_autowipefree char *password = NULL;
> > > 
> > > and have it result in memset+free
> > > 
> > 
> > That is perfect.
> > When do you think you could post the series so that I could rebase
> > on top of it?
> 
> 
> I am thinking that I will keep my patch as is, just so that code is
> consistent in memsetting the secrets (even though as Nir pointed out,
> that these will be probably optimized away anyway).
> And then when you send your patch you will just remove all
> of these memsets.

I'm fine with you continuing to use memset, since this is a pre-existing
problem in the code that you are not making worse. We'll figure out the
fix separately.

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 [this message]
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
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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