Hello, As you will see from the below DSA, a class of vulnerabilities in perl programs has been announced today. We have fixed the worst parts of this in Debian, but ultimately we'd like to (in keeping with upstream's intentions for 5.26) remove the current directory from the module search path altogether.
At the moment, this would cause around 40 packages to FTBFS (that was the number of jessie - it will be a bit different for sid). In the near term, changing the default is a matter of uncommenting a line in a conffile (and can therefore be easily reverted by the user if needed). I'd like to upload such a change to sid ASAP (probably just after the initial sid upload, due any minute now, migrates to testing). If the impact of that measured against sid/stretch is manageable, we'd also like to consider making the change by default in a future point release, although the number of packages that need updates may still be too large; we'd obviously discuss that with you in the normal way via a transition bug. Are you happy for us to introduce such a change in sid later this week, and start filing RC bugs about problems in other packages caused by the change? Thanks, Dominic. ----- Forwarded message from Salvatore Bonaccorso <[email protected]> ----- Date: Mon, 25 Jul 2016 14:18:38 +0000 From: Salvatore Bonaccorso <[email protected]> To: [email protected] Subject: [SECURITY] [DSA 3628-1] perl security update ------------------------------------------------------------------------- Debian Security Advisory DSA-3628-1 [email protected] 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 [email protected] . 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: [email protected] ----- End forwarded message -----
