linux-cve-announce - CVE-2022-50455: nfs: fix possible null-ptr-deref when parsing param

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Message-ID: <2025100118-CVE-2022-50455-24fb@gregkh>
Date: Wed,  1 Oct 2025 13:45:25 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2022-50455: nfs: fix possible null-ptr-deref when parsing param

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

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

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

nfs: fix possible null-ptr-deref when parsing param

According to commit "vfs: parse: deal with zero length string value",
kernel will set the param->string to null pointer in vfs_parse_fs_string()
if fs string has zero length.

Yet the problem is that, nfs_fs_context_parse_param() will dereferences the
param->string, without checking whether it is a null pointer, which may
trigger a null-ptr-deref bug.

This patch solves it by adding sanity check on param->string
in nfs_fs_context_parse_param().

The Linux kernel CVE team has assigned CVE-2022-50455 to this issue.


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

	Fixed in 6.0.16 with commit 46819f604557fe7bc39a6c352fd368371aa9cd6e
	Fixed in 6.1.2 with commit 55513864b418c6453d68aebc36cffcf965342426
	Fixed in 6.2 with commit 5559405df652008e56eee88872126fe4c451da67

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-2022-50455
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:
	fs/nfs/fs_context.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/46819f604557fe7bc39a6c352fd368371aa9cd6e
	https://git.kernel.org/stable/c/55513864b418c6453d68aebc36cffcf965342426
	https://git.kernel.org/stable/c/5559405df652008e56eee88872126fe4c451da67