linux-cve-announce - CVE-2022-49400: md: Don't set mddev private to NULL in raid0 pers->free

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Message-ID: <2025022650-CVE-2022-49400-0754@gregkh>
Date: Wed, 26 Feb 2025 03:11:14 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: CVE-2022-49400: md: Don't set mddev private to NULL in raid0 pers->free

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

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

md: Don't set mddev private to NULL in raid0 pers->free

In normal stop process, it does like this:
   do_md_stop
      |
   __md_stop (pers->free(); mddev->private=NULL)
      |
   md_free (free mddev)
__md_stop sets mddev->private to NULL after pers->free. The raid device
will be stopped and mddev memory is free. But in reshape, it doesn't
free the mddev and mddev will still be used in new raid.

In reshape, it first sets mddev->private to new_pers and then runs
old_pers->free(). Now raid0 sets mddev->private to NULL in raid0_free.
The new raid can't work anymore. It will panic when dereference
mddev->private because of NULL pointer dereference.

It can panic like this:
[63010.814972] kernel BUG at drivers/md/raid10.c:928!
[63010.819778] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
[63010.825011] CPU: 3 PID: 44437 Comm: md0_resync Kdump: loaded Not tainted 5.14.0-86.el9.x86_64 #1
[63010.833789] Hardware name: Dell Inc. PowerEdge R6415/07YXFK, BIOS 1.15.0 09/11/2020
[63010.841440] RIP: 0010:raise_barrier+0x161/0x170 [raid10]
[63010.865508] RSP: 0018:ffffc312408bbc10 EFLAGS: 00010246
[63010.870734] RAX: 0000000000000000 RBX: ffffa00bf7d39800 RCX: 0000000000000000
[63010.877866] RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffa00bf7d39800
[63010.884999] RBP: 0000000000000000 R08: fffffa4945e74400 R09: 0000000000000000
[63010.892132] R10: ffffa00eed02f798 R11: 0000000000000000 R12: ffffa00bbc435200
[63010.899266] R13: ffffa00bf7d39800 R14: 0000000000000400 R15: 0000000000000003
[63010.906399] FS:  0000000000000000(0000) GS:ffffa00eed000000(0000) knlGS:0000000000000000
[63010.914485] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[63010.920229] CR2: 00007f5cfbe99828 CR3: 0000000105efe000 CR4: 00000000003506e0
[63010.927363] Call Trace:
[63010.929822]  ? bio_reset+0xe/0x40
[63010.933144]  ? raid10_alloc_init_r10buf+0x60/0xa0 [raid10]
[63010.938629]  raid10_sync_request+0x756/0x1610 [raid10]
[63010.943770]  md_do_sync.cold+0x3e4/0x94c
[63010.947698]  md_thread+0xab/0x160
[63010.951024]  ? md_write_inc+0x50/0x50
[63010.954688]  kthread+0x149/0x170
[63010.957923]  ? set_kthread_struct+0x40/0x40
[63010.962107]  ret_from_fork+0x22/0x30

Removing the code that sets mddev->private to NULL in raid0 can fix
problem.

The Linux kernel CVE team has assigned CVE-2022-49400 to this issue.


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

	Issue introduced in 5.15.17 with commit 00e3d58f50a875343124bcf5a9637520a492b0d1 and fixed in 5.15.46 with commit f63fd1e0e0fc158023cc67ea6a07e278019061ba
	Issue introduced in 5.17 with commit 0c031fd37f69deb0cd8c43bbfcfccd62ebd7e952 and fixed in 5.17.14 with commit b7a51df785031cc49caf1c59766ca89cfa97b54b
	Issue introduced in 5.17 with commit 0c031fd37f69deb0cd8c43bbfcfccd62ebd7e952 and fixed in 5.18.3 with commit 7da3454a65f8a56e65dfb44fa0ccac08cbc2f5a1
	Issue introduced in 5.17 with commit 0c031fd37f69deb0cd8c43bbfcfccd62ebd7e952 and fixed in 5.19 with commit 0f2571ad7a30ff6b33cde142439f9378669f8b4f
	Issue introduced in 5.16.3 with commit 92053ae0398a58c6914e807d5e070297ba8cfe88

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-2022-49400
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/md/raid0.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/f63fd1e0e0fc158023cc67ea6a07e278019061ba
	https://git.kernel.org/stable/c/b7a51df785031cc49caf1c59766ca89cfa97b54b
	https://git.kernel.org/stable/c/7da3454a65f8a56e65dfb44fa0ccac08cbc2f5a1
	https://git.kernel.org/stable/c/0f2571ad7a30ff6b33cde142439f9378669f8b4f