Package: exim4
Version: 4.87-3
Severity: important
Hi maintainer,
An update for this package has been released as part of our handling for
the issue described below. This fixes an instance of the dynamic module
loading vulnerability alluded to.
I attach the patch I applied for jessie; please could you review this
and apply something similar for sid?
Thanks,
Dominic.
----- Forwarded message from Salvatore Bonaccorso <car...@debian.org> -----
Date: Mon, 25 Jul 2016 14:18:38 +0000
From: Salvatore Bonaccorso <car...@debian.org>
To: debian-security-annou...@lists.debian.org
Subject: [SECURITY] [DSA 3628-1] perl security update
-------------------------------------------------------------------------
Debian Security Advisory DSA-3628-1 secur...@debian.org
https://www.debian.org/security/ Salvatore Bonaccorso
July 25, 2016 https://www.debian.org/security/faq
-------------------------------------------------------------------------
Package : perl
CVE ID : CVE-2016-1238 CVE-2016-6185
Debian Bug : 829578
Multiple vulnerabilities were discovered in the implementation of the
Perl programming language. The Common Vulnerabilities and Exposures
project identifies the following problems:
CVE-2016-1238
John Lightsey and Todd Rinaldo reported that the opportunistic
loading of optional modules can make many programs unintentionally
load code from the current working directory (which might be changed
to another directory without the user realising) and potentially
leading to privilege escalation, as demonstrated in Debian with
certain combinations of installed packages.
The problem relates to Perl loading modules from the includes
directory array ("@INC") in which the last element is the current
directory ("."). That means that, when "perl" wants to load a module
(during first compilation or during lazy loading of a module in run-
time), perl will look for the module in the current directory at the
end, since '.' is the last include directory in its array of include
directories to seek. The issue is with requiring libraries that are
in "." but are not otherwise installed.
With this update several modules which are known to be vulnerable
are updated to not load modules from current directory.
Additionally the update allows configurable removal of "." from @INC
in /etc/perl/sitecustomize.pl for a transitional period. It is
recommended to enable this setting if the possible breakage for a
specific site has been evaluated. Problems in packages provided in
Debian resulting from the switch to the removal of '.' from @INC
should be reported to the Perl maintainers at
p...@packages.debian.org .
It is planned to switch to the default removal of '.' in @INC in a
subsequent update to perl via a point release if possible, and in
any case for the upcoming stable release Debian 9 (stretch).
CVE-2016-6185
It was discovered that XSLoader, a core module from Perl to
dynamically load C libraries into Perl code, could load shared
library from incorrect location. XSLoader uses caller() information
to locate the .so file to load. This can be incorrect if
XSLoader::load() is called in a string eval. An attacker can take
advantage of this flaw to execute arbitrary code.
For the stable distribution (jessie), these problems have been fixed in
version 5.20.2-3+deb8u6. Additionally this update includes the
following updated packages to address optional module loading
vulnerabilities related to CVE-2016-1238, or to address build failures
which occur when '.' is removed from @INC:
- cdbs 0.4.130+deb8u1
- debhelper 9.20150101+deb8u2
- devscripts 2.15.3+deb8u1
- exim4 4.84.2-2+deb8u1
- libintl-perl 1.23-1+deb8u1
- libmime-charset-perl 1.011.1-1+deb8u2
- libmime-encwords-perl 1.014.3-1+deb8u1
- libmodule-build-perl 0.421000-2+deb8u1
- libnet-dns-perl 0.81-2+deb8u1
- libsys-syslog-perl 0.33-1+deb8u1
- libunicode-linebreak-perl 0.0.20140601-2+deb8u2
We recommend that you upgrade your perl packages.
Further information about Debian Security Advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://www.debian.org/security/
Mailing list: debian-security-annou...@lists.debian.org
----- End forwarded message -----
diff -Nru exim4-4.84.2/debian/changelog exim4-4.84.2/debian/changelog
--- exim4-4.84.2/debian/changelog 2016-03-13 17:45:53.000000000 +0000
+++ exim4-4.84.2/debian/changelog 2016-07-24 22:45:57.000000000 +0100
@@ -1,3 +1,10 @@
+exim4 (4.84.2-1+deb8u1) jessie-security; urgency=high
+
+ * Non-maintainer upload.
+ * eximstats: Remove . from @INC [CVE-2016-1238]
+
+ -- Dominic Hargreaves <d...@earth.li> Sun, 24 Jul 2016 22:35:48 +0100
+
exim4 (4.84.2-1) jessie-security; urgency=high
* New upstream security release.
diff -Nru exim4-4.84.2/debian/patches/90_CVE-2016-1238.diff exim4-4.84.2/debian/patches/90_CVE-2016-1238.diff
--- exim4-4.84.2/debian/patches/90_CVE-2016-1238.diff 1970-01-01 01:00:00.000000000 +0100
+++ exim4-4.84.2/debian/patches/90_CVE-2016-1238.diff 2016-07-24 22:36:32.000000000 +0100
@@ -0,0 +1,11 @@
+--- a/src/eximstats.src 2016-07-24 22:29:53.000000000 +0100
++++ b/src/eximstats.src 2016-07-24 22:33:49.763365395 +0100
+@@ -550,6 +550,8 @@
+
+ =cut
+
++BEGIN { pop @INC if $INC[-1] eq '.' }
++
+ use integer;
+ use strict;
+ use IO::File;
diff -Nru exim4-4.84.2/debian/patches/series exim4-4.84.2/debian/patches/series
--- exim4-4.84.2/debian/patches/series 2016-03-13 17:45:53.000000000 +0000
+++ exim4-4.84.2/debian/patches/series 2016-07-24 22:34:36.000000000 +0100
@@ -18,3 +18,4 @@
87_Fix-transport-results-pipe-for-multiple-recipients-c.patch
89_01_only_warn_on_nonempty_environment.diff
89_02_Store-the-initial-working-directory.diff
+90_CVE-2016-1238.diff
