Subject: CVE-2021-47086: phonet/pep: refuse to enable an unbound pipe

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

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

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

phonet/pep: refuse to enable an unbound pipe

This ioctl() implicitly assumed that the socket was already bound to
a valid local socket name, i.e. Phonet object. If the socket was not
bound, two separate problems would occur:

1) We'd send an pipe enablement request with an invalid source object.
2) Later socket calls could BUG on the socket unexpectedly being
   connected yet not bound to a valid object.

The Linux kernel CVE team has assigned CVE-2021-47086 to this issue.

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

	Fixed in 4.4.297 with commit 0bbdd62ce9d4
	Fixed in 4.9.295 with commit b10c7d745615
	Fixed in 4.14.260 with commit 311601f11485
	Fixed in 4.19.223 with commit 982b6ba1ce62
	Fixed in 5.4.169 with commit 48c76fc53582
	Fixed in 5.10.89 with commit 52ad5da8e316
	Fixed in 5.15.12 with commit 53ccdc73eeda
	Fixed in 5.16 with commit 75a2f3152009

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-2021-47086
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:
	net/phonet/pep.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/0bbdd62ce9d44f3a22059b3d20a0df977d9f6d59
	https://git.kernel.org/stable/c/b10c7d745615a092a50c2e03ce70446d2bec2aca
	https://git.kernel.org/stable/c/311601f114859d586d5ef8833d60d3aa23282161
	https://git.kernel.org/stable/c/982b6ba1ce626ef87e5c29f26f2401897554f235
	https://git.kernel.org/stable/c/48c76fc53582e7f13c1e0b11c916e503256c4d0b
	https://git.kernel.org/stable/c/52ad5da8e316fa11e3a50b3f089aa63e4089bf52
	https://git.kernel.org/stable/c/53ccdc73eedaf0e922c45b569b797d2796fbaafa
	https://git.kernel.org/stable/c/75a2f31520095600f650597c0ac41f48b5ba0068