Subject: CVE-2021-47235: net: ethernet: fix potential use-after-free in ec_bhf_remove

From: Greg Kroah-Hartman <[email-masked]>

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

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

net: ethernet: fix potential use-after-free in ec_bhf_remove

static void ec_bhf_remove(struct pci_dev *dev)
{
...
	struct ec_bhf_priv *priv = netdev_priv(net_dev);

	unregister_netdev(net_dev);
	free_netdev(net_dev);

	pci_iounmap(dev, priv->dma_io);
	pci_iounmap(dev, priv->io);
...
}

priv is netdev private data, but it is used
after free_netdev(). It can cause use-after-free when accessing priv
pointer. So, fix it by moving free_netdev() after pci_iounmap()
calls.

The Linux kernel CVE team has assigned CVE-2021-47235 to this issue.

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

	Issue introduced in 3.15 with commit 6af55ff52b02 and fixed in 4.4.274 with commit db2bc3cfd2bc
	Issue introduced in 3.15 with commit 6af55ff52b02 and fixed in 4.9.274 with commit 1cafc540b7bf
	Issue introduced in 3.15 with commit 6af55ff52b02 and fixed in 4.14.238 with commit b1ad28375509
	Issue introduced in 3.15 with commit 6af55ff52b02 and fixed in 4.19.196 with commit 0260916843cc
	Issue introduced in 3.15 with commit 6af55ff52b02 and fixed in 5.4.128 with commit 19f88ca68ccf
	Issue introduced in 3.15 with commit 6af55ff52b02 and fixed in 5.10.46 with commit 95deeb29d831
	Issue introduced in 3.15 with commit 6af55ff52b02 and fixed in 5.12.13 with commit d11d79e52ba0
	Issue introduced in 3.15 with commit 6af55ff52b02 and fixed in 5.13 with commit 9cca0c2d7014

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-2021-47235
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/ec_bhf.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/db2bc3cfd2bc01621014d4f17cdfc74611f339c8
	https://git.kernel.org/stable/c/1cafc540b7bf1b6a5a77dc000205fe337ef6eba6
	https://git.kernel.org/stable/c/b1ad283755095a4b9d1431aeb357d7df1a33d3bb
	https://git.kernel.org/stable/c/0260916843cc74f3906acf8b6f256693e01530a2
	https://git.kernel.org/stable/c/19f88ca68ccf8771276a606765239b167654f84a
	https://git.kernel.org/stable/c/95deeb29d831e2fae608439e243e7a520611e7ea
	https://git.kernel.org/stable/c/d11d79e52ba080ee567cb7d7eb42a5ade60a8130
	https://git.kernel.org/stable/c/9cca0c2d70149160407bda9a9446ce0c29b6e6c6