David's Blog

SSL Certificates

david — Mon, 12 Jul 2010 21:19:36 +0000

I’m currently trying to set up mallard with a proper ssl certificate (free ones are available from www.startssl.com). The authority requires some sort of client certificate form of authentication to login to their site. Unfortunately Chrome from Linux doesn’t yet support this properly. After much googling I found that I could export my certificate from Chrome and then import it into Firefox:
pk12util -o certfile.p12 -d sql:$HOME/.pki/nssdb -n
The certificate’s name is obtained running
certutil -d sql:$HOME/.pki/nssdb -L

(Source: serverfault)

F-Spot Facebook Extension Bug

david — Fri, 18 Sep 2009 11:34:55 +0000

There is a bug in the f-spot facebook extension included with Ubuntu Gutsy and Intrepid (F-Spot crashes during authorization exporting to Facebook if friend IDs are large). Didn’t want to wait until Jaunty to upload pictures to Facebook, so I’ve compiled FacebookExport.dll using the upstream patch and copied it over /usr/lib/f-spot/extensions/FacebookExport.dll (making a backup of course!). Works for me, but no gaurentees.

ntpd

david — Fri, 02 Jan 2009 00:18:26 +0000

ntpd is now working on mallard (so the clock is nolonger 3min slow). Apparently
restrict -4 default ignore
was to strict to actually synchronise with other servers, but
restrict -4 default noquery nomodify nopeer notrap
seems to work.

Results (at last)

david — Tue, 15 Jul 2008 20:00:43 +0000

It seems to be the done thing to comment on your results here, so I’ll give a brief overview of mine.

Analogue and Digital Filters, etc, I was quite happy with, though confused as to why about three courses are lumped into one line. Advanced Digital synthesis- well aparently a B- plus a B- plus an A makes 76%.. makes sense?

Like Ben I was surpised by Comms, didn’t think the result went as well as I’d thought the exam went. Distributed Computing was my best exam, though I did least work for it. I was quite pleased with the ECADs (70% in Media and 72% in Music - pretty good esp considering I’m rubbish at lab books and I didn’t really care anymore when I handed them in). In SWEng I got 76%, which I was quite happy with. Does anyone know if we get any feedback on SWEng?

So, 79% for the year, bringing my average done to 79%. So as long as I don’t screw up too much next year..

Pretending to be an IMAP server using netcat

david — Wed, 11 Jun 2008 23:07:57 +0000

So, say you want to pretend to be an imap server using nc (can’t think of any good reason why you’d want to do this, we were trying to seriously confuse an iphone). So, you do something like:

cat - | nc -l -p 143 -v

And when the line

connect to [127.0.0.1] from localhost [127.0.0.1] 39656

appears you type

* OK myIMAPserver

If the client is you pretending to be an imap client or even mutt, you’ll find that you get a response. If, on the other hand, the client is an iPhone, you’ll get absolutely nothing. Why? Because the RFC for IMAP states:

All interactions transmitted by client and server are in the form of
lines; that is, strings that end with a CRLF.

CR is a carriage return (ascii code 0d), LF is a line feed (ascii code 0a)

But netcat doesn’t believe in sending CRs (fair enough I suppose, unix uses LF as the new line character, with windows using the CRLF pair). On OSX you can coax nc into sending a CRLF by typing CTRL+V and then pressing return twice. Once you do that, the iPhone starts talking to you (in a REALLY insecure manner, but that’s another story

Fun.

gnome-screensaver

david — Sat, 24 Nov 2007 20:45:45 +0000

Spent a couple of hours trying to fix the screen saver on my laptop. The unlock dialog box refused to appear, so you had to press ctrl-alt-F1, login to the console and killall gnome-screensaver to get back to the desktop.

This FAQ gave me a few hints. I found I was getting errors like:
Unable to establish service gnome-screensaver: Critical error - immediate abort

When I looked in /var/log/authlog I found the line:
Nov 24 19:39:24 localhost gnome-screensaver-dialog: PAM _pam_load_conf_file: unable to open /etc/pam.d/common-password

chmod 644 /etc/pam.d/common-password fixed the problem. I have no idea how this file ended up with the wrong permissions.

Mallard moves again

david — Tue, 23 Oct 2007 00:09:52 +0000

This morning mallard moved the 30 miles or so (back) to Redbus Sovereign House from Rapidswitch’s Maidenhead data centre with only about 15 minutes of down time. Not bad considering Google thinks the journey alone should have taken 1hr 10min.

Timetables

david — Mon, 01 Oct 2007 16:55:08 +0000

Our timetables have appeared.

Debian Etch

david — Tue, 11 Sep 2007 22:22:09 +0000

I upgraded the server that hosts this site from Sarge to Etch yesterday. I then paniced when I typed ‘ps aux’ and saw the line

102 7353 0.0 2.3 11632 3040 ? Ss Sep10 0:00 /usr/sbin/exim4 -bd -q30m

The 102 really should have read “Debian-exim”. This concerned me for a long time (not least of all because exim was also having difficulty connecting to the sql database). Then I discovered that the new version of ps’s reaction to long usernames is to display the uid instead. So where on sarge it displayed “Debian-”, on Etch it displays 102. I had presumed that nss was screwed or something. But apparently not. Panic over.

pam-pgsql

david — Tue, 04 Sep 2007 18:16:13 +0000

Whilst pam_pgsql logins will work with crypted passwords in your db without the line “pw_type = crypt”, passwd (the password changing utility) won’t. With the line, passwd does.