linux-cve-announce - CVE-2022-50314: nbd: Fix hung when signal interrupts nbd_start_device

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Message-ID: <2025091500-CVE-2022-50314-9a10@gregkh>
Date: Mon, 15 Sep 2025 16:46:16 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2022-50314: nbd: Fix hung when signal interrupts nbd_start_device_ioctl()

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

nbd: Fix hung when signal interrupts nbd_start_device_ioctl()

syzbot reported hung task [1].  The following program is a simplified
version of the reproducer:

int main(void)
{
	int sv[2], fd;

	if (socketpair(AF_UNIX, SOCK_STREAM, 0, sv) < 0)
		return 1;
	if ((fd = open("/dev/nbd0", 0)) < 0)
		return 1;
	if (ioctl(fd, NBD_SET_SIZE_BLOCKS, 0x81) < 0)
		return 1;
	if (ioctl(fd, NBD_SET_SOCK, sv[0]) < 0)
		return 1;
	if (ioctl(fd, NBD_DO_IT) < 0)
		return 1;
	return 0;
}

When signal interrupt nbd_start_device_ioctl() waiting the condition
atomic_read(&config->recv_threads) == 0, the task can hung because it
waits the completion of the inflight IOs.

This patch fixes the issue by clearing queue, not just shutdown, when
signal interrupt nbd_start_device_ioctl().

The Linux kernel CVE team has assigned CVE-2022-50314 to this issue.


Affected and fixed versions
===========================

	Fixed in 4.14.296 with commit 3ba3846cb3e2fb3c6fbf79e998472821b298419e
	Fixed in 4.19.262 with commit c7b4641bd2395c2f3cd3b0a0cbf292ed9d489398
	Fixed in 5.4.220 with commit 3575949513ea3b387b30dac1e69468a923c86caf
	Fixed in 5.10.150 with commit b2700f98b3f4dd19fb4315b70581e5caff89eb49
	Fixed in 5.15.75 with commit c0d73be0af8c1310713bc39a8d7a22e35084e14f
	Fixed in 5.19.17 with commit 62006a72b05e0d38727eef5188700f2488be5e89
	Fixed in 6.0.3 with commit 35fb7d4a53d9e36d1b91161ea9870d9c6d57dccf
	Fixed in 6.1 with commit 1de7c3cf48fc41cd95adb12bd1ea9033a917798a

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2022-50314
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/block/nbd.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/3ba3846cb3e2fb3c6fbf79e998472821b298419e
	https://git.kernel.org/stable/c/c7b4641bd2395c2f3cd3b0a0cbf292ed9d489398
	https://git.kernel.org/stable/c/3575949513ea3b387b30dac1e69468a923c86caf
	https://git.kernel.org/stable/c/b2700f98b3f4dd19fb4315b70581e5caff89eb49
	https://git.kernel.org/stable/c/c0d73be0af8c1310713bc39a8d7a22e35084e14f
	https://git.kernel.org/stable/c/62006a72b05e0d38727eef5188700f2488be5e89
	https://git.kernel.org/stable/c/35fb7d4a53d9e36d1b91161ea9870d9c6d57dccf
	https://git.kernel.org/stable/c/1de7c3cf48fc41cd95adb12bd1ea9033a917798a