From: "Philippe Mathieu-Daudé" <philmd@redhat.com>
To: qemu-devel@nongnu.org
Cc: "Fam Zheng" <fam@euphon.net>, "Kevin Wolf" <kwolf@redhat.com>,
"Vladimir Sementsov-Ogievskiy" <vsementsov@virtuozzo.com>,
qemu-block@nongnu.org, "Markus Armbruster" <armbru@redhat.com>,
"Max Reitz" <mreitz@redhat.com>, "Bandan Das" <bsd@redhat.com>,
"Prasad J Pandit" <ppandit@redhat.com>,
"Philippe Mathieu-Daudé" <philmd@redhat.com>
Subject: [PATCH 3/3] docs/secure-coding-practices: Describe null-co/zeroes-co block drivers
Date: Wed, 10 Mar 2021 12:43:14 +0100 [thread overview]
Message-ID: <20210310114314.1068957-4-philmd@redhat.com> (raw)
In-Reply-To: <20210310114314.1068957-1-philmd@redhat.com>
Document that security reports must not use the 'null-co' block
driver, as it leaves memory uninitialized on purposed (this is
a performance feature).
Reports must be send using the 'zeroes-co' driver.
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
docs/devel/secure-coding-practices.rst | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/docs/devel/secure-coding-practices.rst b/docs/devel/secure-coding-practices.rst
index cbfc8af67e6..64d61085804 100644
--- a/docs/devel/secure-coding-practices.rst
+++ b/docs/devel/secure-coding-practices.rst
@@ -104,3 +104,10 @@ structures and only process the local copy. This prevents
time-of-check-to-time-of-use (TOCTOU) race conditions that could cause QEMU to
crash when a vCPU thread modifies guest RAM while device emulation is
processing it.
+
+Use of null-co / zeroes-co block drivers
+----------------------------------------
+
+When reporting security issues, the null-co block driver must not be used,
+as it is designed for performance and its read accesses are not initialized.
+The zeroes-co block driver must be used instead.
--
2.26.2
next prev parent reply other threads:[~2021-03-10 11:48 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-10 11:43 [PATCH 0/3] block: Introduce the 'zeroes-co' driver to help security reports Philippe Mathieu-Daudé
2021-03-10 11:43 ` [PATCH 1/3] block: Introduce the 'zeroes-co' driver Philippe Mathieu-Daudé
2021-03-10 11:43 ` [RFC PATCH 2/3] tests/test-blockjob: Use zeroes-co instead of null-co, read-zeroes=on Philippe Mathieu-Daudé
2021-03-10 11:43 ` Philippe Mathieu-Daudé [this message]
2021-03-10 12:40 ` [PATCH 3/3] docs/secure-coding-practices: Describe null-co/zeroes-co block drivers Vladimir Sementsov-Ogievskiy
2021-03-10 11:55 ` [PATCH 0/3] block: Introduce the 'zeroes-co' driver to help security reports Daniel P. Berrangé
2021-03-10 12:29 ` Philippe Mathieu-Daudé
2021-03-10 12:32 ` Fam Zheng
2021-03-10 12:37 ` Philippe Mathieu-Daudé
2021-03-10 14:24 ` Fam Zheng
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