Better living through software

Ben Hutchings's diary of life and technology

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Mon, 06 Jul 2015

Debian LTS work, June 2015

This was my seventh month working on Debian LTS. I was assigned 14.75 hours of work by Freexian's Debian LTS initiative.


I did not receive any feedback from upstream for my proposed fix for CVE-2015-1038 mentioned last month, so I went ahead and uploaded it based on my own testing. (I also uploaded the fix to wheezy-security, jessie-security and sid.)

Afterwards, I received a request from upstream for a patch against their latest release (even the version in sid is quite a long way behind that), so I ported the fix forward to that.


I backported further security fixes, but had to give up on one (CVE-2014-8172, AIO soft lockup) as the fix depends on wide-ranging changes. For CVE-2015-1805 (pipe iovec overrun leading to memory corruption), the upstream fix was also not applicable, but this looked so serious that we needed to fix it anyway. Red Hat had already fixed this in their 2.6.32-based kernel and they didn't have overlapping changes to the pipe implementation, so I was able to extract this fix from their source tarball. I uploaded and issued DLA-246-1.

Unfortunately, I failed to notice that Linux had introduced two regressions that were fixed in While these didn't appear in my testing, one of them did affect several users that were quick to upgrade. I applied the upstream fixes, made a second upload and issued DLA-246-2.

I also triaged the issues that are still unfixed, and I spent some time working on a fix for CVE-2015-1350 (unprivileged chown removes setcap attribute), but I haven't yet completed the backport to 2.6.32 or tested it.


I looked at OpenSSL, which is still marked as affected by CVE-2015-4000 (encryption downgrade aka Logjam). After discussion with the LTS team I made a note of the current situation, which is that a full fix (rejecting Diffie-Hellman keys shorter than 1024 bits) must wait until more servers have been upgraded.

posted at: 14:03 | path: / | permanent link to this entry