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From: Fam Zheng <fam@euphon.net>
To: "Philippe Mathieu-Daudé" <philmd@redhat.com>
Cc: Laurent Vivier <lvivier@redhat.com>,
	Kevin Wolf <kwolf@redhat.com>, Thomas Huth <thuth@redhat.com>,
	qemu-block@nongnu.org, Markus Armbruster <armbru@redhat.com>,
	qemu-devel@nongnu.org,
	Wainer dos Santos Moschetta <wainersm@redhat.com>,
	Max Reitz <mreitz@redhat.com>, Alexander Bulekov <alxndr@bu.edu>,
	Bandan Das <bsd@redhat.com>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Cleber Rosa <crosa@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH v2 0/2] block: Use 'read-zeroes=true' mode by default with 'null-co' driver
Date: Mon, 22 Feb 2021 17:35:32 +0000	[thread overview]
Message-ID: <20210222173532.GA117898@ip-172-44-255-31> (raw)
In-Reply-To: <38dd38eb-af59-8baf-b908-fb6c4e842cd1@redhat.com>

On 2021-02-19 15:09, Philippe Mathieu-Daudé wrote:
> On 2/19/21 12:07 PM, Max Reitz wrote:
> > On 13.02.21 22:54, Fam Zheng wrote:
> >> On 2021-02-11 15:26, Philippe Mathieu-Daudé wrote:
> >>> The null-co driver doesn't zeroize buffer in its default config,
> >>> because it is designed for testing and tests want to run fast.
> >>> However this confuses security researchers (access to uninit
> >>> buffers).
> >>
> >> I'm a little surprised.
> >>
> >> Is changing default the only way to fix this? I'm not opposed to
> >> changing the default but I'm not convinced this is the easiest way.
> >> block/nvme.c also doesn't touch the memory, but defers to the device
> >> DMA, why doesn't that confuse the security checker?
> 
> Generally speaking, there is a balance between security and performance.
> We try to provide both, but when we can't, my understanding is security
> is more important.

Why is hiding the code path behind a non-default more secure? What is
not secure now?

Fam



  reply	other threads:[~2021-02-22 17:39 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-11 14:26 [PATCH v2 0/2] block: Use 'read-zeroes=true' mode by default with 'null-co' driver Philippe Mathieu-Daudé
2021-02-11 14:26 ` [PATCH v2 1/2] block: Explicit null-co uses 'read-zeroes=false' Philippe Mathieu-Daudé
2021-02-11 16:29   ` Vladimir Sementsov-Ogievskiy
2021-02-11 19:19     ` Philippe Mathieu-Daudé
2021-02-11 22:40   ` Eric Blake
2021-02-11 23:49     ` Philippe Mathieu-Daudé
2021-02-12 11:34     ` Vladimir Sementsov-Ogievskiy
2021-02-12 19:06   ` Eric Blake
2021-02-11 14:26 ` [PATCH v2 2/2] block/null: Enable 'read-zeroes' mode by default Philippe Mathieu-Daudé
2021-02-11 16:22   ` Stefan Hajnoczi
2021-02-11 15:42 ` [PATCH v2 0/2] block: Use 'read-zeroes=true' mode by default with 'null-co' driver Alexander Bulekov
2021-02-12 14:32   ` Philippe Mathieu-Daudé
2021-02-13 21:54 ` Fam Zheng
2021-02-19 11:07   ` Max Reitz
2021-02-19 14:09     ` Philippe Mathieu-Daudé
2021-02-22 17:35       ` Fam Zheng [this message]
2021-02-22 17:55         ` Philippe Mathieu-Daudé
2021-02-23  9:21           ` Fam Zheng
2021-02-23 16:01             ` Max Reitz
2021-02-23 17:21               ` Fam Zheng
2021-02-22 18:15       ` Daniel P. Berrangé
2021-02-22 18:36         ` Philippe Mathieu-Daudé
2021-02-23  8:44         ` Max Reitz
2021-02-23  9:29           ` Daniel P. Berrangé

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