Archive for April, 2013

Webkitgtk & SSL

April 30, 2013

For a project of mine I created a small app based on webkitgtk that talks to a SSL server.

And I almost forgot about the libsoup default behavior for SSL certificates checking. By default libsoup and therefore webkitgtk will not do any SSL certificate checks. You need to put something like the following snippet into your code (adjust for your language of choice):

from gi.repository import WebKit

session = WebKit.get_default_session()
session.set_property("ssl-use-system-ca-file", True)

If you don’t do this it will accept any certificate (including self-signed ones).

This is documented behavior in libsoup and they don’t want to change it for compatiblity reasons in libsoup. But for webkit its unexpected behavior (at least to me) and I hope the webkitgtk developers will consider changing this default in webkit. I filed a bug about it. So if you use webkitgtk and SSL, remember to set the above property.

PassHash cmdline

April 18, 2013

I use the PassHash firefox extension to generate site-specific strong passwords. The idea behind the extension is that a master password and a siteTag (e.g. the domain name) is used to generate a sha1 hash. This hash is used as the password for the website. In python its essentially this code:

h = hmac.new(master_pass, site_tag, hashlib.sha1)
print(b64encode(h.digest())[:hash_len])

I want a commandline utility that can output me PassHash compatible hashes when I use w3m (or if the extension stops working for some reason).

To my delight I discovered that the upstream git repNice and hard to brute-force.o of PassHash already has a python helper to generate passhash compatible password. I added some tweaks to add pythons argparse [1] and now I’m really happy with it:

$ ./tools/passhash.py --hash-size 14 slashdot.org
Please enter the master key: 
KPXveo7bq7j1%X

Hard to brute-force and matches what the extension generates.

squid-deb-proxy for Debian

April 11, 2013

I uploaded squid-deb-proxy into Debian unstable today and its in the NEW queue. I created it back in the days of Ubuntu 10.04 and some people voiced interest in having it in Debian as well so I spend a bit of time to get it customized for Debian.

Squid-deb-proxy uses the well known squid proxy with a custom configuration to cache deb package and Indexfiles (like Packages.gz) that will allow caching from the default archives and mirrors and reject anything else by default.

The basic philosophy is that “it just works”. You run on your server:

root@server# apt-get install squid-deb-proxy

and on your clients:

root@client# apt-get install squid-deb-proxy-client

and that’s it. It does not require any fiddling with configuration (unless you want to 😉 ). The default will let you connect to .debian.org and nothing else.

The server will announce itself via avahi as _apt_proxy._tcp and the
client will hook into apt to use Acquire::http::ProxyAutoDetect. The
client is useful for other servers that announce themself via avahi.

Packaging was a bit more work than anticipated because there is a bit of setup and teardown work in the initscript. For Debian as sysvinit script was needed, Ubuntu uses upstart so it took a bit of refactoring to extract the code into a common helper.

If you want to try it now, its available via:

$ bzr branch lp:squid-deb-proxy
$ cd squid-deb-proxy
$ bzr-buildpackage

and in unstable once it leaves the NEW queue.