Arch Linux Security Advisory ASA-201810-8
=========================================

Severity: High
Date    : 2018-10-09
CVE-ID  : CVE-2018-6951 CVE-2018-6952 CVE-2018-1000156
Package : patch
Type    : multiple issues
Remote  : No
Link    : https://security.archlinux.org/AVG-619

Summary
=======

The package patch before version 2.7.6-3 is vulnerable to multiple
issues including arbitrary command execution and denial of service.

Resolution
==========

Upgrade to 2.7.6-3.

# pacman -Syu "patch>=2.7.6-3"

The problems have been fixed upstream but no release is available yet.

Workaround
==========

None.

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

- CVE-2018-6951 (denial of service)

An issue was discovered in GNU patch through 2.7.6. There is a
segmentation fault, associated with a NULL pointer dereference, leading
to a denial of service in the intuit_diff_type function in pch.c, aka a
"mangled rename" issue.

- CVE-2018-6952 (denial of service)

A double free exists in the another_hunk function in pch.c in GNU patch
through 2.7.6. An attacker could potentially use this flaw to crash the
patch utility by tricking it into processing crafted patches.

- CVE-2018-1000156 (arbitrary command execution)

An arbitrary command execution vulnerability has been found in patch
versions prior to 2.7.7 when applying ed-style patches. Due to
insufficient sanitization of the input patch stream, it is possible for
a patch file to cause patch to pass certain ed scripts to the ed
editor, which would run commands. This issue could be exploited to
execute arbitrary commands as the user invoking patch against a
specially crafted patch file, which could be leveraged to obtain
elevated privileges.

Impact
======

An attacker can execute arbitrary commands or crash the patch utility
via a specially crafted patch file.

References
==========

https://bugs.archlinux.org/task/57526
https://savannah.gnu.org/bugs/?53132
https://git.savannah.gnu.org/cgit/patch.git/commit/?id=f290f48a621867084884bfff87f8093c15195e6a
https://savannah.gnu.org/bugs/?53133
https://git.savannah.gnu.org/cgit/patch.git/commit/?id=9c986353e420ead6e706262bf204d6e03322c300
https://savannah.gnu.org/bugs/?53566
https://git.savannah.gnu.org/cgit/patch.git/commit/?id=123eaff0d5d1aebe128295959435b9ca5909c26d
https://security.archlinux.org/CVE-2018-6951
https://security.archlinux.org/CVE-2018-6952
https://security.archlinux.org/CVE-2018-1000156