linux-cve-announce - CVE-2022-49926: net: dsa: Fix possible memory leaks in dsa_loop

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Message-ID: <2025050110-CVE-2022-49926-d9bc@gregkh>
Date: Thu,  1 May 2025 16:11:56 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2022-49926: net: dsa: Fix possible memory leaks in dsa_loop_init()

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

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

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

net: dsa: Fix possible memory leaks in dsa_loop_init()

kmemleak reported memory leaks in dsa_loop_init():

kmemleak: 12 new suspected memory leaks

unreferenced object 0xffff8880138ce000 (size 2048):
  comm "modprobe", pid 390, jiffies 4295040478 (age 238.976s)
  backtrace:
    [<000000006a94f1d5>] kmalloc_trace+0x26/0x60
    [<00000000a9c44622>] phy_device_create+0x5d/0x970
    [<00000000d0ee2afc>] get_phy_device+0xf3/0x2b0
    [<00000000dca0c71f>] __fixed_phy_register.part.0+0x92/0x4e0
    [<000000008a834798>] fixed_phy_register+0x84/0xb0
    [<0000000055223fcb>] dsa_loop_init+0xa9/0x116 [dsa_loop]
    ...

There are two reasons for memleak in dsa_loop_init().

First, fixed_phy_register() create and register phy_device:

fixed_phy_register()
  get_phy_device()
    phy_device_create() # freed by phy_device_free()
  phy_device_register() # freed by phy_device_remove()

But fixed_phy_unregister() only calls phy_device_remove().
So the memory allocated in phy_device_create() is leaked.

Second, when mdio_driver_register() fail in dsa_loop_init(),
it just returns and there is no cleanup for phydevs.

Fix the problems by catching the error of mdio_driver_register()
in dsa_loop_init(), then calling both fixed_phy_unregister() and
phy_device_free() to release phydevs.
Also add a function for phydevs cleanup to avoid duplacate.

The Linux kernel CVE team has assigned CVE-2022-49926 to this issue.


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

	Issue introduced in 4.12 with commit 98cd1552ea27e512c7e99e2aa76042a26e4fb25c and fixed in 4.14.299 with commit 935b4beb724946a37cebf97191592d4879d3a3a3
	Issue introduced in 4.12 with commit 98cd1552ea27e512c7e99e2aa76042a26e4fb25c and fixed in 4.19.265 with commit d593e1ede655b74c42e4e4fe285ea64aee96fb5c
	Issue introduced in 4.12 with commit 98cd1552ea27e512c7e99e2aa76042a26e4fb25c and fixed in 5.4.224 with commit bbc5d7b46a729bfcbb5544f6612b7a67dd4f4d6f
	Issue introduced in 4.12 with commit 98cd1552ea27e512c7e99e2aa76042a26e4fb25c and fixed in 5.10.154 with commit 37a098fc9b42bd7fce66764866aa514639667b6e
	Issue introduced in 4.12 with commit 98cd1552ea27e512c7e99e2aa76042a26e4fb25c and fixed in 5.15.78 with commit 9f555b1584fc2d5d16ee3c4d9438e93ac7c502c7
	Issue introduced in 4.12 with commit 98cd1552ea27e512c7e99e2aa76042a26e4fb25c and fixed in 6.0.8 with commit 4d2024b138d9f7b02ae13ee997fd3a71e9e46254
	Issue introduced in 4.12 with commit 98cd1552ea27e512c7e99e2aa76042a26e4fb25c and fixed in 6.1 with commit 633efc8b3dc96f56f5a57f2a49764853a2fa3f50

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-2022-49926
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/dsa/dsa_loop.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/935b4beb724946a37cebf97191592d4879d3a3a3
	https://git.kernel.org/stable/c/d593e1ede655b74c42e4e4fe285ea64aee96fb5c
	https://git.kernel.org/stable/c/bbc5d7b46a729bfcbb5544f6612b7a67dd4f4d6f
	https://git.kernel.org/stable/c/37a098fc9b42bd7fce66764866aa514639667b6e
	https://git.kernel.org/stable/c/9f555b1584fc2d5d16ee3c4d9438e93ac7c502c7
	https://git.kernel.org/stable/c/4d2024b138d9f7b02ae13ee997fd3a71e9e46254
	https://git.kernel.org/stable/c/633efc8b3dc96f56f5a57f2a49764853a2fa3f50