From: Max Reitz <mreitz@redhat.com>
To: "Fam Zheng" <fam@euphon.net>,
"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, qemu-devel@nongnu.org,
Wainer dos Santos Moschetta <wainersm@redhat.com>,
Markus Armbruster <armbru@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: Fri, 19 Feb 2021 12:07:17 +0100 [thread overview]
Message-ID: <3da6a2aa-472e-d9e1-b803-303891513274@redhat.com> (raw)
In-Reply-To: <20210213215448.GA67780@ip-172-44-255-31>
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?
>
> Cannot we just somehow annotate it in a way that the checker can
> understand (akin to how we provide coverity models) and be done?
The question is, why wouldn’t we change the default? read-zeroes=true
seems the better default to me. I consider silencing valgrind warnings
and the like a nice side effect.
Max
next prev parent reply other threads:[~2021-02-19 11:08 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 [this message]
2021-02-19 14:09 ` Philippe Mathieu-Daudé
2021-02-22 17:35 ` Fam Zheng
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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