Message-ID: <2025100757-CVE-2022-50545-f879@gregkh>
Date: Tue,  7 Oct 2025 17:21:03 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2022-50545: r6040: Fix kmemleak in probe and remove

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

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

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

r6040: Fix kmemleak in probe and remove

There is a memory leaks reported by kmemleak:

  unreferenced object 0xffff888116111000 (size 2048):
    comm "modprobe", pid 817, jiffies 4294759745 (age 76.502s)
    hex dump (first 32 bytes):
      00 c4 0a 04 81 88 ff ff 08 10 11 16 81 88 ff ff  ................
      08 10 11 16 81 88 ff ff 00 00 00 00 00 00 00 00  ................
    backtrace:
      [<ffffffff815bcd82>] kmalloc_trace+0x22/0x60
      [<ffffffff827e20ee>] phy_device_create+0x4e/0x90
      [<ffffffff827e6072>] get_phy_device+0xd2/0x220
      [<ffffffff827e7844>] mdiobus_scan+0xa4/0x2e0
      [<ffffffff827e8be2>] __mdiobus_register+0x482/0x8b0
      [<ffffffffa01f5d24>] r6040_init_one+0x714/0xd2c [r6040]
      ...

The problem occurs in probe process as follows:
  r6040_init_one:
    mdiobus_register
      mdiobus_scan    <- alloc and register phy_device,
                         the reference count of phy_device is 3
    r6040_mii_probe
      phy_connect     <- connect to the first phy_device,
                         so the reference count of the first
                         phy_device is 4, others are 3
    register_netdev   <- fault inject succeeded, goto error handling path

    // error handling path
    err_out_mdio_unregister:
      mdiobus_unregister(lp->mii_bus);
    err_out_mdio:
      mdiobus_free(lp->mii_bus);    <- the reference count of the first
                                       phy_device is 1, it is not released
                                       and other phy_devices are released
  // similarly, the remove process also has the same problem

The root cause is traced to the phy_device is not disconnected when
removes one r6040 device in r6040_remove_one() or on error handling path
after r6040_mii probed successfully. In r6040_mii_probe(), a net ethernet
device is connected to the first PHY device of mii_bus, in order to
notify the connected driver when the link status changes, which is the
default behavior of the PHY infrastructure to handle everything.
Therefore the phy_device should be disconnected when removes one r6040
device or on error handling path.

Fix it by adding phy_disconnect() when removes one r6040 device or on
error handling path after r6040_mii probed successfully.

The Linux kernel CVE team has assigned CVE-2022-50545 to this issue.


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

	Issue introduced in 2.6.36 with commit 3831861b4ad8fd0ad7110048eb3e155628799d2b and fixed in 4.9.337 with commit a04707f4596952049da05756c27398c34d9a1d36
	Issue introduced in 2.6.36 with commit 3831861b4ad8fd0ad7110048eb3e155628799d2b and fixed in 4.14.303 with commit b4448816e6a565e08236a6009c6bf48c6836cdfd
	Issue introduced in 2.6.36 with commit 3831861b4ad8fd0ad7110048eb3e155628799d2b and fixed in 4.19.270 with commit 2ce242e1b9ad31c1f68496b3548e407a8cb2c07d
	Issue introduced in 2.6.36 with commit 3831861b4ad8fd0ad7110048eb3e155628799d2b and fixed in 5.4.229 with commit b0a61359026b57a287a48fbb4ba1d097023eca3e
	Issue introduced in 2.6.36 with commit 3831861b4ad8fd0ad7110048eb3e155628799d2b and fixed in 5.10.163 with commit 3d5f83a62e8235d235534b3dc6f197d8a822c269
	Issue introduced in 2.6.36 with commit 3831861b4ad8fd0ad7110048eb3e155628799d2b and fixed in 5.15.86 with commit 9b5b50329e2e966831a7237dd6949e7b5362a49a
	Issue introduced in 2.6.36 with commit 3831861b4ad8fd0ad7110048eb3e155628799d2b and fixed in 6.0.16 with commit ad2c8f25457ca9a81e7e958148cbc26600ce3071
	Issue introduced in 2.6.36 with commit 3831861b4ad8fd0ad7110048eb3e155628799d2b and fixed in 6.1.2 with commit 5944c25c67de54e0aa53623e1e1af3bf8b16ed44
	Issue introduced in 2.6.36 with commit 3831861b4ad8fd0ad7110048eb3e155628799d2b and fixed in 6.2 with commit 7e43039a49c2da45edc1d9d7c9ede4003ab45a5f

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-2022-50545
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/ethernet/rdc/r6040.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/a04707f4596952049da05756c27398c34d9a1d36
	https://git.kernel.org/stable/c/b4448816e6a565e08236a6009c6bf48c6836cdfd
	https://git.kernel.org/stable/c/2ce242e1b9ad31c1f68496b3548e407a8cb2c07d
	https://git.kernel.org/stable/c/b0a61359026b57a287a48fbb4ba1d097023eca3e
	https://git.kernel.org/stable/c/3d5f83a62e8235d235534b3dc6f197d8a822c269
	https://git.kernel.org/stable/c/9b5b50329e2e966831a7237dd6949e7b5362a49a
	https://git.kernel.org/stable/c/ad2c8f25457ca9a81e7e958148cbc26600ce3071
	https://git.kernel.org/stable/c/5944c25c67de54e0aa53623e1e1af3bf8b16ed44
	https://git.kernel.org/stable/c/7e43039a49c2da45edc1d9d7c9ede4003ab45a5f

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