January 31st 2017

Free software activities in January 2017

Here is my monthly update covering what I have been doing in the free software world (previous month):

Reproducible builds


Whilst anyone can inspect the source code of free software for malicious flaws, most software is distributed pre-compiled to end users.

The motivation behind the Reproducible Builds effort is to permit verification that no flaws have been introduced — either maliciously or accidentally — during this compilation process by promising identical results are always generated from a given source, thus allowing multiple third-parties to come to a consensus on whether a build was compromised.

(I have previously been awarded a grant from the Core Infrastructure Initiative to fund my work in this area.)

This month I:

I also made the following changes to our tooling:

diffoscope

diffoscope is our in-depth and content-aware diff utility that can locate and diagnose reproducibility issues.

  • Comparators:
    • Display magic file type when we know the file format but can't find file-specific details. (Closes: #850850).
    • Ensure our "APK metadata" file appears first, fixing non-deterministic tests. (998b288)
    • Fix APK extration with absolute filenames. (Closes: #850485).
    • Don't error if directory containing ELF debug symbols already exists. (Closes: #850807).
    • Support comparing .ico files (Closes: #850730).
    • If we don't have a tool (eg. apktool), don't blow up when attempting to unpack it.
  • Output formats:
    • Add Markdown output format. (Closes: #848141).
    • Add RestructuredText output format.
    • Use an optimised indentation routine throughout all presenters.
    • Move text presenter to use the Visitor pattern.
    • Correctly escape value of href="" elements (re. #849411).
  • Tests:
    • Prevent FTBFS by loading fixtures as UTF-8 in case surrounding terminal is not Unicode-aware. (Closes: #852926).
    • Skip tests if binutils can't handle the object file format. (Closes: #851588).
    • Actually compare the output of text/ReST/Markdown formats to fixtures.
    • Add tests for: Comparing two empty directories, HTML output, image.ICOImageFile, --html-dir, --text-color & no arguments (beyond the filenames) emits the text output.
  • Profiling:
    • Count the number of calls, not just the total time.
    • Skip as much profiling overhead when not enabled for a ~2% speedup.
  • Misc:
    • Alias an expensive Config() lookup for a 10% optimisation.
    • Avoid expensive regex creation until we actually need it, speeding up diff parsing by 2X.
    • Use Pythonic logging functions based on __name__, etc.
    • Drop milliseconds from logging output.

buildinfo.debian.net

buildinfo.debian.net is my experiment into how to process, store and distribute .buildinfo files after the Debian archive software has processed them.

  • Store files directly onto S3.
  • Drop big unique_together index to save disk space.
  • Show SHA256 checksums where space permits.

Debian LTS


This month I have been paid to work 12.75 hours on Debian Long Term Support (LTS). In that time I did the following:

  • "Frontdesk" duties, triaging CVEs, etc.
  • Issued DLA 773-1 for python-crypto fixing a vulnerability where calling AES.new with an invalid parameter could crash the Python interpreter.
  • Issued DLA 777-1 for libvncserver addressing two heap-based buffer overflow attacks based on invalid FramebufferUpdate data.
  • Issued DLA 778-1 for pcsc-lite correcting a use-after-free vulnerability.
  • Issued DLA 795-1 for hesiod which fixed a weak SUID check as well as removed the hard-coding of a fallback domain if the configuration file could not be found.
  • Issued DLA 810-1 for libarchive fixing a heap buffer overflow.

Uploads

  • python-django:
    • 1:1.10.5-1 — New upstream stable release.
    • 1:1.11~alpha1-1 — New upstream experimental release.
  • gunicorn (19.6.0-10) — Moved debian/README.Debian to debian/NEWS so that the recent important changes will be displayed to users when upgrading to stretch.
  • redis:
    • 3:3.2.6-2 & 4:4.0-rc2-2 — Tidy patches and rename RunTimeDirectory to RuntimeDirectory in .service files. (Closes: #850534)
    • 3:3.2.6-3 — Remove a duplicate redis-server binary by symlinking /usr/bin/redis-check-rdb. This was found by the dedup service.
    • 3:3.2.6-4 — Expand the documentation in redis-server.service and redis-sentinel.service regarding the default hardening options and how, in most installations, they can be increased.
    • 3:3.2.6-5, 3:3.2.6-6, 4:4.0-rc2-3 & 4:4.0-rc2-4 — Add taskset calls to try and avoid build failures due to parallelism in upstream test suite.

I also made the following non-maintainer uploads:

  • cpio:
    • 2.12+dfsg-1 — New upstream release (to experimental), refreshing all patches, etc.
    • 2.12+dfsg-2 — Add missing autoconf to Build-Depends.
  • xjump (2.7.5-6.2) — Make the build reproducible by passing -n to gzip calls in debian/rules. (Closes: #777354)
  • magicfilter (1.2-64.1) — Make the build reproducible by passing -n to gzip calls in debian/rules. (Closes: #777478)



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