From: Alexander Bulekov <alxndr@bu.edu>
To: "Philippe Mathieu-Daudé" <philmd@redhat.com>
Cc: Fam Zheng <fam@euphon.net>, Laurent Vivier <lvivier@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>,
Kevin Wolf <kwolf@redhat.com>, Bandan Das <bsd@redhat.com>,
Stefan Hajnoczi <stefanha@redhat.com>,
Cleber Rosa <crosa@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Max Reitz <mreitz@redhat.com>
Subject: Re: [PATCH v2 0/2] block: Use 'read-zeroes=true' mode by default with 'null-co' driver
Date: Thu, 11 Feb 2021 10:42:28 -0500 [thread overview]
Message-ID: <20210211154228.izwdqb33dxtnu65n@mozz.bu.edu> (raw)
In-Reply-To: <20210211142656.3818078-1-philmd@redhat.com>
On 210211 1526, 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).
>
Interesting.. Is there an example bug report, where it raised alarms
because of an un-zeroed null-co:// buffer?
-Alex
> A one-line patch supposed which became a painful one, because
> there is so many different syntax to express the same usage:
>
> opt = qdict_new();
> qdict_put_str(opt, "read-zeroes", "off");
> null_bs = bdrv_open("null-co://", NULL, opt, BDRV_O_RDWR | BDRV_O_PROTOCOL,
> &error_abort);
>
> vm.qmp('blockdev-add', driver='null-co', read_zeroes=False, ...)
>
> vm.add_drive_raw("id=drive0,driver=null-co,read-zeroes=off,if=none")
>
> blk0 = { 'node-name': 'src',
> 'driver': 'null-co',
> 'read-zeroes': 'off' }
>
> 'file': {
> 'driver': 'null-co',
> 'read-zeroes': False,
> }
>
> "file": {
> "driver": "null-co",
> "read-zeroes": "off"
> }
>
> { "execute": "blockdev-add",
> "arguments": {
> "driver": "null-co",
> "read-zeroes": false,
> "node-name": "disk0"
> }
> }
>
> opts = {'driver': 'null-co,read-zeroes=off', 'node-name': 'root', 'size': 1024}
>
> qemu -drive driver=null-co,read-zeroes=off
>
> qemu-io ... "json:{'driver': 'null-co', 'read-zeroes': false, 'size': 65536}"
>
> qemu-img null-co://,read-zeroes=off
>
> qemu-img ... -o data_file="json:{'driver':'null-co',,'read-zeroes':false,,'size':'4294967296'}"
>
> There are probably more.
>
> Anyhow, the iotests I am not sure and should be audited are 056, 155
> (I don't understand the syntax) and 162.
>
> Please review,
>
> Phil.
>
> Philippe Mathieu-Daud=C3=A9 (2):
> block: Explicit null-co uses 'read-zeroes=3Dfalse'
> block/null: Enable 'read-zeroes' mode by default
>
> docs/devel/testing.rst | 14 +++++++-------
> tests/qtest/fuzz/generic_fuzz_configs.h | 11 ++++++-----
> block/null.c | 2 +-
> tests/test-bdrv-drain.c | 10 ++++++++--
> tests/acceptance/virtio_check_params.py | 2 +-
> tests/perf/block/qcow2/convert-blockstatus | 6 +++---
> tests/qemu-iotests/040 | 2 +-
> tests/qemu-iotests/041 | 12 ++++++++----
> tests/qemu-iotests/051 | 2 +-
> tests/qemu-iotests/051.out | 2 +-
> tests/qemu-iotests/051.pc.out | 4 ++--
> tests/qemu-iotests/087 | 6 ++++--
> tests/qemu-iotests/118 | 2 +-
> tests/qemu-iotests/133 | 2 +-
> tests/qemu-iotests/153 | 8 ++++----
> tests/qemu-iotests/184 | 2 ++
> tests/qemu-iotests/184.out | 10 +++++-----
> tests/qemu-iotests/218 | 3 +++
> tests/qemu-iotests/224 | 3 ++-
> tests/qemu-iotests/224.out | 8 ++++----
> tests/qemu-iotests/225 | 2 +-
> tests/qemu-iotests/227 | 4 ++--
> tests/qemu-iotests/227.out | 4 ++--
> tests/qemu-iotests/228 | 2 +-
> tests/qemu-iotests/235 | 1 +
> tests/qemu-iotests/245 | 2 +-
> tests/qemu-iotests/270 | 2 +-
> tests/qemu-iotests/283 | 3 ++-
> tests/qemu-iotests/283.out | 4 ++--
> tests/qemu-iotests/299 | 1 +
> tests/qemu-iotests/299.out | 2 +-
> tests/qemu-iotests/300 | 4 ++--
> 32 files changed, 82 insertions(+), 60 deletions(-)
>
> --=20
> 2.26.2
>
>
next prev parent reply other threads:[~2021-02-11 15:47 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 ` Alexander Bulekov [this message]
2021-02-12 14:32 ` [PATCH v2 0/2] block: Use 'read-zeroes=true' mode by default with 'null-co' driver 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
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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