linux-cve-announce - CVE-2025-21636: sctp: sysctl: plpmtud_probe

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <2025011943-CVE-2025-21636-0bb0@gregkh>
Date: Sun, 19 Jan 2025 11:17:45 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: CVE-2025-21636: sctp: sysctl: plpmtud_probe_interval: avoid using current->nsproxy

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

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

sctp: sysctl: plpmtud_probe_interval: avoid using current->nsproxy

As mentioned in a previous commit of this series, using the 'net'
structure via 'current' is not recommended for different reasons:

- Inconsistency: getting info from the reader's/writer's netns vs only
  from the opener's netns.

- current->nsproxy can be NULL in some cases, resulting in an 'Oops'
  (null-ptr-deref), e.g. when the current task is exiting, as spotted by
  syzbot [1] using acct(2).

The 'net' structure can be obtained from the table->data using
container_of().

Note that table->data could also be used directly, as this is the only
member needed from the 'net' structure, but that would increase the size
of this fix, to use '*data' everywhere 'net->sctp.probe_interval' is
used.

The Linux kernel CVE team has assigned CVE-2025-21636 to this issue.


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

	Issue introduced in 5.14 with commit d1e462a7a5f359cbb9a0e8fbfafcfb6657034105 and fixed in 6.1.125 with commit 44ee8635922b6eb940faddb961a8347c6857d722
	Issue introduced in 5.14 with commit d1e462a7a5f359cbb9a0e8fbfafcfb6657034105 and fixed in 6.6.72 with commit 284a221f8fa503628432c7bb5108277c688c6ffa
	Issue introduced in 5.14 with commit d1e462a7a5f359cbb9a0e8fbfafcfb6657034105 and fixed in 6.12.10 with commit bcf8c60074e81ed2ac2d35130917175a3949c917
	Issue introduced in 5.14 with commit d1e462a7a5f359cbb9a0e8fbfafcfb6657034105 and fixed in 6.13-rc7 with commit 6259d2484d0ceff42245d1f09cc8cb6ee72d847a

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-2025-21636
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:
	net/sctp/sysctl.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/44ee8635922b6eb940faddb961a8347c6857d722
	https://git.kernel.org/stable/c/284a221f8fa503628432c7bb5108277c688c6ffa
	https://git.kernel.org/stable/c/bcf8c60074e81ed2ac2d35130917175a3949c917
	https://git.kernel.org/stable/c/6259d2484d0ceff42245d1f09cc8cb6ee72d847a