linux-cve-announce - CVE-2025-37875: igc: fix PTM cycle trigger logic

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: <2025050900-CVE-2025-37875-71e0@gregkh>
Date: Fri,  9 May 2025 08:44:09 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-37875: igc: fix PTM cycle trigger logic

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

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

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

igc: fix PTM cycle trigger logic

Writing to clear the PTM status 'valid' bit while the PTM cycle is
triggered results in unreliable PTM operation. To fix this, clear the
PTM 'trigger' and status after each PTM transaction.

The issue can be reproduced with the following:

$ sudo phc2sys -R 1000 -O 0 -i tsn0 -m

Note: 1000 Hz (-R 1000) is unrealistically large, but provides a way to
quickly reproduce the issue.

PHC2SYS exits with:

"ioctl PTP_OFFSET_PRECISE: Connection timed out" when the PTM transaction
  fails

This patch also fixes a hang in igc_probe() when loading the igc
driver in the kdump kernel on systems supporting PTM.

The igc driver running in the base kernel enables PTM trigger in
igc_probe().  Therefore the driver is always in PTM trigger mode,
except in brief periods when manually triggering a PTM cycle.

When a crash occurs, the NIC is reset while PTM trigger is enabled.
Due to a hardware problem, the NIC is subsequently in a bad busmaster
state and doesn't handle register reads/writes.  When running
igc_probe() in the kdump kernel, the first register access to a NIC
register hangs driver probing and ultimately breaks kdump.

With this patch, igc has PTM trigger disabled most of the time,
and the trigger is only enabled for very brief (10 - 100 us) periods
when manually triggering a PTM cycle.  Chances that a crash occurs
during a PTM trigger are not 0, but extremely reduced.

The Linux kernel CVE team has assigned CVE-2025-37875 to this issue.

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

	Issue introduced in 5.15 with commit a90ec84837325df4b9a6798c2cc0df202b5680bd and fixed in 5.15.181 with commit c1f174edaccc5a00f8e218c42a0aa9156efd5f76
	Issue introduced in 5.15 with commit a90ec84837325df4b9a6798c2cc0df202b5680bd and fixed in 6.1.135 with commit 0c03e4fbe1321697d9d04587e21e416705e1b19f
	Issue introduced in 5.15 with commit a90ec84837325df4b9a6798c2cc0df202b5680bd and fixed in 6.6.88 with commit 16194ca3f3b4448a062650c869a7b3b206c6f5d3
	Issue introduced in 5.15 with commit a90ec84837325df4b9a6798c2cc0df202b5680bd and fixed in 6.12.25 with commit f3516229cd12dcd45f23ed01adab17e8772b1bd5
	Issue introduced in 5.15 with commit a90ec84837325df4b9a6798c2cc0df202b5680bd and fixed in 6.14.4 with commit 31959e06143692f7e02b8eef7d7d6ac645637906
	Issue introduced in 5.15 with commit a90ec84837325df4b9a6798c2cc0df202b5680bd and fixed in 6.15-rc3 with commit 8e404ad95d2c10c261e2ef6992c7c12dde03df0e

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-2025-37875
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/net/ethernet/intel/igc/igc_defines.h
	drivers/net/ethernet/intel/igc/igc_ptp.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/c1f174edaccc5a00f8e218c42a0aa9156efd5f76
	https://git.kernel.org/stable/c/0c03e4fbe1321697d9d04587e21e416705e1b19f
	https://git.kernel.org/stable/c/16194ca3f3b4448a062650c869a7b3b206c6f5d3
	https://git.kernel.org/stable/c/f3516229cd12dcd45f23ed01adab17e8772b1bd5
	https://git.kernel.org/stable/c/31959e06143692f7e02b8eef7d7d6ac645637906
	https://git.kernel.org/stable/c/8e404ad95d2c10c261e2ef6992c7c12dde03df0e