Subject: CVE-2022-48740: selinux: fix double free of cond_list on error paths

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

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

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

selinux: fix double free of cond_list on error paths

On error path from cond_read_list() and duplicate_policydb_cond_list()
the cond_list_destroy() gets called a second time in caller functions,
resulting in NULL pointer deref.  Fix this by resetting the
cond_list_len to 0 in cond_list_destroy(), making subsequent calls a
noop.

Also consistently reset the cond_list pointer to NULL after freeing.

[PM: fix line lengths in the description]

The Linux kernel CVE team has assigned CVE-2022-48740 to this issue.

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

	Fixed in 5.10.99 with commit f446089a268c
	Fixed in 5.15.22 with commit 70caa32e6d81
	Fixed in 5.16.8 with commit 7ed9cbf7ac0d
	Fixed in 5.17 with commit 186edf7e368c

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-2022-48740
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:
	security/selinux/ss/conditional.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/f446089a268c8fc6908488e991d28a9b936293db
	https://git.kernel.org/stable/c/70caa32e6d81f45f0702070c0e4dfe945e92fbd7
	https://git.kernel.org/stable/c/7ed9cbf7ac0d4ed86b356e1b944304ae9ee450d4
	https://git.kernel.org/stable/c/186edf7e368c40d06cf727a1ad14698ea67b74ad