linux-cve-announce - CVE-2022-50092: dm thin: fix use-after-free crash in dm_sm_register_threshold

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Message-ID: <2025061801-CVE-2022-50092-dcb8@gregkh>
Date: Wed, 18 Jun 2025 13:02:37 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2022-50092: dm thin: fix use-after-free crash in dm_sm_register_threshold_callback

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

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

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

dm thin: fix use-after-free crash in dm_sm_register_threshold_callback

Fault inject on pool metadata device reports:
  BUG: KASAN: use-after-free in dm_pool_register_metadata_threshold+0x40/0x80
  Read of size 8 at addr ffff8881b9d50068 by task dmsetup/950

  CPU: 7 PID: 950 Comm: dmsetup Tainted: G        W         5.19.0-rc6 #1
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014
  Call Trace:
   <TASK>
   dump_stack_lvl+0x34/0x44
   print_address_description.constprop.0.cold+0xeb/0x3f4
   kasan_report.cold+0xe6/0x147
   dm_pool_register_metadata_threshold+0x40/0x80
   pool_ctr+0xa0a/0x1150
   dm_table_add_target+0x2c8/0x640
   table_load+0x1fd/0x430
   ctl_ioctl+0x2c4/0x5a0
   dm_ctl_ioctl+0xa/0x10
   __x64_sys_ioctl+0xb3/0xd0
   do_syscall_64+0x35/0x80
   entry_SYSCALL_64_after_hwframe+0x46/0xb0

This can be easily reproduced using:
  echo offline > /sys/block/sda/device/state
  dd if=/dev/zero of=/dev/mapper/thin bs=4k count=10
  dmsetup load pool --table "0 20971520 thin-pool /dev/sda /dev/sdb 128 0 0"

If a metadata commit fails, the transaction will be aborted and the
metadata space maps will be destroyed. If a DM table reload then
happens for this failed thin-pool, a use-after-free will occur in
dm_sm_register_threshold_callback (called from
dm_pool_register_metadata_threshold).

Fix this by in dm_pool_register_metadata_threshold() by returning the
-EINVAL error if the thin-pool is in fail mode. Also fail pool_ctr()
with a new error message: "Error registering metadata threshold".

The Linux kernel CVE team has assigned CVE-2022-50092 to this issue.


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

	Issue introduced in 3.10 with commit ac8c3f3df65e487bbcabf274eeeb9cd222f5da1e and fixed in 5.4.211 with commit 05cef0999b3208b5a6ede1bfac855139e4de55ef
	Issue introduced in 3.10 with commit ac8c3f3df65e487bbcabf274eeeb9cd222f5da1e and fixed in 5.10.137 with commit 5e2cf705155a1514be3c96ea664a9cd356998ee7
	Issue introduced in 3.10 with commit ac8c3f3df65e487bbcabf274eeeb9cd222f5da1e and fixed in 5.15.61 with commit f83131a3071a0b61a4d7dca70f95adb3ffad920e
	Issue introduced in 3.10 with commit ac8c3f3df65e487bbcabf274eeeb9cd222f5da1e and fixed in 5.18.18 with commit 1a199fa9217d28511ff88529238fd9980ea64cf3
	Issue introduced in 3.10 with commit ac8c3f3df65e487bbcabf274eeeb9cd222f5da1e and fixed in 5.19.2 with commit e4dbe24f4bfd8377e7ba79fdcdb7c4d6eb1c6790
	Issue introduced in 3.10 with commit ac8c3f3df65e487bbcabf274eeeb9cd222f5da1e and fixed in 6.0 with commit 3534e5a5ed2997ca1b00f44a0378a075bd05e8a3

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-2022-50092
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/dm-thin-metadata.c
	drivers/md/dm-thin.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/05cef0999b3208b5a6ede1bfac855139e4de55ef
	https://git.kernel.org/stable/c/5e2cf705155a1514be3c96ea664a9cd356998ee7
	https://git.kernel.org/stable/c/f83131a3071a0b61a4d7dca70f95adb3ffad920e
	https://git.kernel.org/stable/c/1a199fa9217d28511ff88529238fd9980ea64cf3
	https://git.kernel.org/stable/c/e4dbe24f4bfd8377e7ba79fdcdb7c4d6eb1c6790
	https://git.kernel.org/stable/c/3534e5a5ed2997ca1b00f44a0378a075bd05e8a3