Tech on Ricky Moorhouse

Disabling SSLv3

Sat, 18 Oct 2014 06:11:17 +0000

With POODLE the time has come to disable SSLv3 everywhere. There will be clients that break and need fixing but it needs doing. You can read more details and background on the vulnerability.

Here's a few useful snippets from my experience with it this week:

Apache

Make sure the combination you have for the SSLProtocol line disables SSLv2 and v3 - something like: SSLProtocol All -SSLv2 -SSLv3

DataPower

Ensure your crypto profiles have SSLv2 and v3 disabled in the options line:

Traffic Pi

Thu, 17 Jul 2014 09:23:54 +0000

Using my Raspberry Pi, Piglow and the traffic API feeds I have created a script to give me a visual representation of the journey time to work. This gives me an idea of the traffic before I leave the house in the morning, or so that when I'm working at home I can look at it and see how glad I am that I'm not sitting in traffic on the way to work :)

Recovering encrypted filesystems

Tue, 25 Feb 2014 10:25:55 +0000

Boot from Live CD / USB
Decrypt the filesystem

<code class="markdown">cryptsetup luksOpen /dev/sda5 <span class="emphasis">*hostname*</span>
</code>

Mount filesystems

<code class="sql">mount /dev/dm-2 /mnt
mount /dev/dm-3 /mnt/home
mount /dev/sda1 /mnt/boot
mount <span class="comment">--bind /dev /mnt/dev</span>
mount <span class="comment">--bind /sys /mnt/sys</span>
mount <span class="comment">--bind /proc /mnt/proc</span>
</code>

Enter chroot chroot /mnt

/etc/crypttab should have: sda5_crypt UUID=sda5_uuid

MySQL Locking

Wed, 15 Sep 2010 15:17:56 +0000

After experimenting a bit with MySQL locking today, I thought I'd make a note of what I'd discovered:

To create a lock, you need to use:

<code>LOCK TABLES table1 [READ |WRITE], table2 [READ |WRITE]</code>

READ is used to stop other people changing the table while you read from it. WRITE is used to stop other people reading the table while you write to it.

Once you have issued a LOCK TABLES statement, you will not have access to any tables you didn't include.

Recover from "Failed to open the relay log"

Mon, 06 Sep 2010 14:17:12 +0000

If you find that after rebooting your MySQL slave it stops replicating with the master and you see the "Failed to open the relay log" error in the logs it is probably caused by MySQL putting it's relay logs in /var/run by default, which gets cleared out on boot.

To fix this, you need to change the location MySQL uses for the logging by adding the following line to the [mysqld] section of /etc/my.cnf

Restore Default Panels

Wed, 24 Mar 2010 09:08:31 +0000

Been using these commands quite a bit recently as I experiment with moving the panels about.

gconftool --recursive-unset /apps/panel pkill gnome-panel

from Watching the Net

Hursley minibus mentioned on BBC News

Thu, 07 May 2009 10:30:50 +0000

I created the twitter feed based on a JSON feed of the geographic location of the minibus provided by my colleague. I then compare the coordinates of the minibus with a set of bounding boxes stored in a database. If the bus is within squares defined in the database, then the pre-defined description is sent to twitter so that anyone following the bus can receive updates as to where it is.

Linux: What is using up disk space?

Mon, 27 Apr 2009 12:50:43 +0000

du -m | sort -nr | head

du -m

summarises disk usage from current path recursively (in megabytes)

sort -nr sorts the output numerically in reverse

head restricts output to the top 10 lines

adapted from Linux Reviews