linux-cve-announce - CVE-2025-39694: s390/sclp: Fix SCCB present check

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: <2025090547-CVE-2025-39694-de23@gregkh>
Date: Fri,  5 Sep 2025 19:21:07 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-39694: s390/sclp: Fix SCCB present check

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

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

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

s390/sclp: Fix SCCB present check

Tracing code called by the SCLP interrupt handler contains early exits
if the SCCB address associated with an interrupt is NULL. This check is
performed after physical to virtual address translation.

If the kernel identity mapping does not start at address zero, the
resulting virtual address is never zero, so that the NULL checks won't
work. Subsequently this may result in incorrect accesses to the first
page of the identity mapping.

Fix this by introducing a function that handles the NULL case before
address translation.

The Linux kernel CVE team has assigned CVE-2025-39694 to this issue.


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

	Issue introduced in 5.16 with commit ada1da31ce34248bc97ca8f801f2cf6efa378a81 and fixed in 6.1.149 with commit aa5073ac1a2a274812f3b04c278992e68ff67cc7
	Issue introduced in 5.16 with commit ada1da31ce34248bc97ca8f801f2cf6efa378a81 and fixed in 6.6.103 with commit 86c2825791c3836a8f77a954b9c5ebe6fab410c5
	Issue introduced in 5.16 with commit ada1da31ce34248bc97ca8f801f2cf6efa378a81 and fixed in 6.12.44 with commit 61605c847599fbfdfafe638607841c7d73719081
	Issue introduced in 5.16 with commit ada1da31ce34248bc97ca8f801f2cf6efa378a81 and fixed in 6.16.4 with commit bf83ae3537359af088d6577812ed93113dfbcb7b
	Issue introduced in 5.16 with commit ada1da31ce34248bc97ca8f801f2cf6efa378a81 and fixed in 6.17-rc3 with commit 430fa71027b6ac9bb0ce5532b8d0676777d4219a

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-2025-39694
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/s390/char/sclp.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/aa5073ac1a2a274812f3b04c278992e68ff67cc7
	https://git.kernel.org/stable/c/86c2825791c3836a8f77a954b9c5ebe6fab410c5
	https://git.kernel.org/stable/c/61605c847599fbfdfafe638607841c7d73719081
	https://git.kernel.org/stable/c/bf83ae3537359af088d6577812ed93113dfbcb7b
	https://git.kernel.org/stable/c/430fa71027b6ac9bb0ce5532b8d0676777d4219a