Date: Mon, 6 Aug 2018 12:27:03 -0400 From: Stéphane Graber <stgraber@...ntu.com> To: lxc-devel@...ts.linuxcontainers.org, lxc-users@...ts.linuxcontainers.org Cc: oss-security@...ts.openwall.com, Matthias Gerstner <mgerstner@...e.de> Subject: CVE-2018-6556: lxc-user-nic allows for open() of arbitrary paths Hello, This is a notice for a security issue affecting the following LXC versions: - 2.0.9 and higher - 3.0.0 and higher Description of the issue: lxc-user-nic (setuid) when asked to delete a network interface will unconditionally open a user provided path. This code path may be used by an unprivileged user to check for the existence of a path which they wouldn't otherwise be able to reach. It may also be used to trigger side effects by causing a (read-only) open of special kernel files (ptmx, proc, sys). This was reported to us by Matthias Gerstner from SUSE and Christian Brauner on the LXC team took care of finding a workable solution and preparing the needed updates. Fixes: - stable-2.0: https://github.com/lxc/lxc/commit/5eb45428b312e978fb9e294dde16efb14dd9fa4d - stable-3.0: https://github.com/lxc/lxc/commit/c1cf54ebf251fdbad1e971679614e81649f1c032 - master: https://github.com/lxc/lxc/commit/f26dc127bf5d66e8c29f8584c64bd97c9bbbc574 Linux distributions were privately notified with about a week notice and so should have security updates ready for this already, or will shortly. We will not be issuing emergency release tarballs for this issue so if you're maintaining your own build, you should be cherry-picking one of the fixes above. We do however intend to release LXC 3.0.2 very shortly which will include this fix among other traditional bugfixes. References: - https://bugs.launchpad.net/ubuntu/+source/lxc/+bug/1783591 - https://bugzilla.suse.com/show_bug.cgi?id=988348 -- Stéphane Graber Ubuntu developer http://www.ubuntu.com Download attachment "signature.asc" of type "application/pgp-signature" (834 bytes)
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