cve/published/2024/CVE-2024-56718.mbox

From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: <linux-cve-announce@vger.kernel.org>
Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org>
Subject: CVE-2024-56718: net/smc: protect link down work from execute after lgr freed

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

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

net/smc: protect link down work from execute after lgr freed

link down work may be scheduled before lgr freed but execute
after lgr freed, which may result in crash. So it is need to
hold a reference before shedule link down work, and put the
reference after work executed or canceled.

The relevant crash call stack as follows:
 list_del corruption. prev->next should be ffffb638c9c0fe20,
    but was 0000000000000000
 ------------[ cut here ]------------
 kernel BUG at lib/list_debug.c:51!
 invalid opcode: 0000 [#1] SMP NOPTI
 CPU: 6 PID: 978112 Comm: kworker/6:119 Kdump: loaded Tainted: G #1
 Hardware name: Alibaba Cloud Alibaba Cloud ECS, BIOS 2221b89 04/01/2014
 Workqueue: events smc_link_down_work [smc]
 RIP: 0010:__list_del_entry_valid.cold+0x31/0x47
 RSP: 0018:ffffb638c9c0fdd8 EFLAGS: 00010086
 RAX: 0000000000000054 RBX: ffff942fb75e5128 RCX: 0000000000000000
 RDX: ffff943520930aa0 RSI: ffff94352091fc80 RDI: ffff94352091fc80
 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffb638c9c0fc38
 R10: ffffb638c9c0fc30 R11: ffffffffa015eb28 R12: 0000000000000002
 R13: ffffb638c9c0fe20 R14: 0000000000000001 R15: ffff942f9cd051c0
 FS:  0000000000000000(0000) GS:ffff943520900000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00007f4f25214000 CR3: 000000025fbae004 CR4: 00000000007706e0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 PKRU: 55555554
 Call Trace:
  rwsem_down_write_slowpath+0x17e/0x470
  smc_link_down_work+0x3c/0x60 [smc]
  process_one_work+0x1ac/0x350
  worker_thread+0x49/0x2f0
  ? rescuer_thread+0x360/0x360
  kthread+0x118/0x140
  ? __kthread_bind_mask+0x60/0x60
  ret_from_fork+0x1f/0x30

The Linux kernel CVE team has assigned CVE-2024-56718 to this issue.


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

	Issue introduced in 5.8 with commit 541afa10c126b6c22c2a805a559c70cc41fd156e and fixed in 6.1.122 with commit bec2f52866d511e94c1c37cd962e4382b1b1a299
	Issue introduced in 5.8 with commit 541afa10c126b6c22c2a805a559c70cc41fd156e and fixed in 6.6.68 with commit 2627c3e8646932dfc7b9722c88c2e1ffcf7a9fb2
	Issue introduced in 5.8 with commit 541afa10c126b6c22c2a805a559c70cc41fd156e and fixed in 6.12.7 with commit 841b1824750d3b8d1dc0a96b14db4418b952abbc
	Issue introduced in 5.8 with commit 541afa10c126b6c22c2a805a559c70cc41fd156e and fixed in 6.13 with commit 2b33eb8f1b3e8c2f87cfdbc8cc117f6bdfabc6ec

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-2024-56718
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_core.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/bec2f52866d511e94c1c37cd962e4382b1b1a299
	https://git.kernel.org/stable/c/2627c3e8646932dfc7b9722c88c2e1ffcf7a9fb2
	https://git.kernel.org/stable/c/841b1824750d3b8d1dc0a96b14db4418b952abbc
	https://git.kernel.org/stable/c/2b33eb8f1b3e8c2f87cfdbc8cc117f6bdfabc6ec