linux-cve-announce - CVE-2025-39857: net/smc: fix one NULL pointer dereference in smc_ib_is_sg_need

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Message-ID: <2025091905-CVE-2025-39857-1658@gregkh>
Date: Fri, 19 Sep 2025 17:28:21 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-39857: net/smc: fix one NULL pointer dereference in smc_ib_is_sg_need_sync()

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

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

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

net/smc: fix one NULL pointer dereference in smc_ib_is_sg_need_sync()

BUG: kernel NULL pointer dereference, address: 00000000000002ec
PGD 0 P4D 0
Oops: Oops: 0000 [#1] SMP PTI
CPU: 28 UID: 0 PID: 343 Comm: kworker/28:1 Kdump: loaded Tainted: G        OE       6.17.0-rc2+ #9 NONE
Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014
Workqueue: smc_hs_wq smc_listen_work [smc]
RIP: 0010:smc_ib_is_sg_need_sync+0x9e/0xd0 [smc]
...
Call Trace:
 <TASK>
 smcr_buf_map_link+0x211/0x2a0 [smc]
 __smc_buf_create+0x522/0x970 [smc]
 smc_buf_create+0x3a/0x110 [smc]
 smc_find_rdma_v2_device_serv+0x18f/0x240 [smc]
 ? smc_vlan_by_tcpsk+0x7e/0xe0 [smc]
 smc_listen_find_device+0x1dd/0x2b0 [smc]
 smc_listen_work+0x30f/0x580 [smc]
 process_one_work+0x18c/0x340
 worker_thread+0x242/0x360
 kthread+0xe7/0x220
 ret_from_fork+0x13a/0x160
 ret_from_fork_asm+0x1a/0x30
 </TASK>

If the software RoCE device is used, ibdev->dma_device is a null pointer.
As a result, the problem occurs. Null pointer detection is added to
prevent problems.

The Linux kernel CVE team has assigned CVE-2025-39857 to this issue.

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

	Issue introduced in 6.0 with commit 0ef69e788411cba2af017db731a9fc62d255e9ac and fixed in 6.1.151 with commit 0cdf1fd8fc59d44a48c694324611136910301ef9
	Issue introduced in 6.0 with commit 0ef69e788411cba2af017db731a9fc62d255e9ac and fixed in 6.6.105 with commit f18d9b3abf9c6587372cc702f963a7592277ed56
	Issue introduced in 6.0 with commit 0ef69e788411cba2af017db731a9fc62d255e9ac and fixed in 6.12.46 with commit eb929910bd4b4165920fa06a87b22cc6cae92e0e
	Issue introduced in 6.0 with commit 0ef69e788411cba2af017db731a9fc62d255e9ac and fixed in 6.16.6 with commit 34f17cbe027050b8d5316ea1b6f9bd7c378e92de
	Issue introduced in 6.0 with commit 0ef69e788411cba2af017db731a9fc62d255e9ac and fixed in 6.17-rc5 with commit ba1e9421cf1a8369d25c3832439702a015d6b5f9

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-2025-39857
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/smc/smc_ib.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/0cdf1fd8fc59d44a48c694324611136910301ef9
	https://git.kernel.org/stable/c/f18d9b3abf9c6587372cc702f963a7592277ed56
	https://git.kernel.org/stable/c/eb929910bd4b4165920fa06a87b22cc6cae92e0e
	https://git.kernel.org/stable/c/34f17cbe027050b8d5316ea1b6f9bd7c378e92de
	https://git.kernel.org/stable/c/ba1e9421cf1a8369d25c3832439702a015d6b5f9