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Posts Tagged ‘Wireless’

Mesh Networking (or 802.11s) comes to Linux

September 4, 2008 Leave a comment

Since kernel 2.6.22 there has been a huge drive to rework and update the entire wireless networking stack in Linux. Back in July, 2.6.26 was released with over 600 wifi specific changes including :

  • mac80211 now supports draft mesh networking (802.11s; thanks to the open80211s project
  • mac80211 now supports more optional HT (802.11n) features
  • mac80211’s monitor interfaces can now be configured more precisely, “cooked” monitors were added
  • mac80211’s IBSS implementation now supports IBSS merging and received various bugfixes
  • mac80211 now has an in-kernel documentation book, help welcome!
  • b43 now has support for PCMCIA devices and QoS/WME

The following have been removed.

  • the bcm43xx driver
  • the old ieee80211softmac code

A while ago I discussed the deprecation of the bcm43xx driver so I welcome its official removal from the kernel as this means less time wasted disabling this legacy kernel module prior to installing / activating b43 on every new install. The mesh networking (draft specification designated 802.11s) support is largly thanks to the open80211s project however it is only in the fairly early stages. Support is not consistent across all the Linux wifi drivers but full support is progressing. I do wonder whether mesh networking will take off, it is however, an exciting concept. Imagine the following scenarios:

1. A dense build up urban area, where multiple nodes (flats / homes etc) could connect via one or two Internet connected nodes.

2. A neighbourhood which contained a lot of like minded PC users each connecting as a node in a local mesh network to create an ‘instant’ LAN/WAN or gaming network. Imagine being about to connect Xbox 360s / PS3 / PSP or even PC gamers wirelessly to your neighbours without using the Internet services.

3. A sparse, less developed environment where multiple nodes are greatly spread out and Internet access is rare.

The possibilities are endless, however with all such technologies, a lot of people need to jump on the bandwagon, particularly with ad-hoc technologies such as these.

Ubuntu 8.04: Hardy Heron on the Amilo 1650

April 25, 2008 15 comments

After using Hardy Heron for about twelve hours now (at least eight of those tweaking and fiddling) I must say I am impressed although, it sometimes feels a bit more clunky than previous releases. This release builds greatly on the previous release 7.10 and feels more feature complete and compatible as well. This is largely due to native inclusion of the b43 driver over the depreciated bcm43xx driver for the wireless as well as an improved restricted driver manager.

Here is an overview of how things work with my Fujitsu Siemens A1650 Amilo laptop:

CPU: Works perfectly (including frequency scaling and power management)

WiFi (Broadcom 4318 ) : Works *! (After the install of Acer_acpi tools and a bit of tweaking)

Graphics (Ati x200m) : Works perfectly! (With Ati Non-Free driver)

Flash (in Firefox) : Works perfectly (I had lots of problems with this in 7.10 Gutsy Gibbon.)

Memory Card Reader : Not tested.

PCMCIA : Works perfectly (tested with IDE > CF converter and tried a CF memory card)

Hot Keys : Can be made to work, but I have not got around to this yet.

* Although it picks up and connects to wireless networks, I need to do a bit of testing before I am 100% sure all the problems have been sorted. Bloody Broadcom….

I had do install a few extra packages to get it all working however and I am going to detail this now.

To get the wireless working we need to install the firmware (not shipped with Ubuntu) via the new firmware cutter b43-fwcutter. In a terminal window, type:

sudo su

sudo apt-get update

sudo apt-get install bc43-fwcutter

Once that is done, follow these instructions to obtain and load the correct firmware module.

Now we need to install the Acer_acpi packages. Do not follow the instructions on the project website relating to acer_acpi as you will end up trying to install the depreciated version of b43 (bcm43xx.)

We need to add the following line to the package manager to enable the repository containing the acer_acpi code:

deb http://www.mumblyworld.info/ubuntu gutsy main

Once that is done, open a console window.

Sudo Su

wget http://www.mumblyworld.info/ubuntu/depot.key -O- | sudo apt-key add -

apt-get update

apt-get install aceracpi-source

m-a prepare

m-a a-i aceracpi-source

This first downloads the repository public signing key and then gets the acer_acpi source package. In the process you will likely be asked to install other dependancies, agree to this as these will be required during the compiling process. Once the above commands have completed, you will need to activate the module:

modprobe acer_acpi

The wireless light on the A1650 will now light up showing the wireless module has been activated. For future reference, it can be activated and deactivated with the following commands:

Sudo su

echo 1 > /proc/acpi/acer/wireless  (to activate)

echo 0 > /proc/acpi/acer/wireless (to deactivate)

Restart and your wireless should be operational :) For reference, I followed parts of the guide found here. I would not recommend you do the same, as you will end up trying to install the depreciate version of the b43 driver, bcm43xx.

Another thing which I installed was the Compiz manager as well as emerald. Compiz has a lot of options, but window decoration is still one I prefer to use Emerald for. These are installed in much the same way as they were in 7.10 with a few key exceptions.

sudo apt-get install compizconfig-settings-manager compiz-fusion-plugins-main compiz-fusion-plugins-extra compiz-gnome compiz-plugins libcompizconfig-backend-gconf libcompizconfig0

Then install emerald:

sudo apt-get install emerald

Once these packages (and their dependancies) have installed, you will find two new options under System > Preferences gnome menu. One will give you complete control over the effects Compiz uses and the other will let you load/tweak and create Emerald themes. However, as per default metacity is the window decorator. In the Compiz “Advanced Desktop Effects Settings” find the window decoration option and replace the command field with “Emerald –replace”

Save and restart if required.

Categories: F/OSS, How To, Linux, News Tags: , , , , ,

Local Client Insecurity

December 23, 2007 Leave a comment

Any tech-savvy user will know of a handful of security vulnerabilities relating to desktop computing, these can range from remote attacks (Man in the middle / Malware / DDoS / Brute Forcing / Port Scanning) to local exploits ( hardware & software keystroke logging / more Malware / dailers etc.)

In-fact, apart from the distant days of Windows 95 I cant recall a time when there were more things for security conscious users to be worried about. Back in the middle to late 90s, the internet was gradually becoming common place and within the reach of the layman. Unfortunately these users typically didn’t (or didn’t have a sufficiently fast connection – 4hrs for IE 4.0 update?) update software to patch security holes. The term script-kiddy was coined, referring to individuals who would use “off the shelf” exploit programs to wreak havoc. These easily found resources would be effective for months (if not years) due to the majority of users being completely clueless or disinterested in protecting their digital homes.

Fast forward to modern day, wireless hacking tools exploiting the poor design and implementation of WEP encryption have been commonplace for a number of years now. Wireless equipment manufacturers have taken on the role of securing their client’s networks by shipping routers with WEP (and more recently WPA) enabled by default which has helped secure many home networks from a variety of threats, from freeloading neighbours to network peeping toms. Security software companies have helped raise awareness while peddling their, often rather poor offerings to the unsuspecting public. (Norton anyone?)

By now everyone must know that running WEP on a Wifi connections is potentially extremely risky, those reading this who are still running an unencrypted Wireless Access point without some kind of secondary encryption system should stop what they are doing and read up on this.

It would appear that even wireless keyboards (using 27Mhz radio transmitters not Bluetooth) are vulnerable (although Bluetooth ones are also but via a different type of attack.) It turns out that security was probably very low down on the list of priorities during development of this common interface extension. The security system emplyed uses a single bit XOR encryption. The best explanation of how rubbish this is stems from TechFaq’s definition / explaination of XOR :

“XOR encryption is a trivially simple symmetric cipher which is used in many applications where security is not a defined requirement.”

The article concludes that there are only 256 possible keys that are set once a keyboard / receiver have been paired with no periodic shifting. It does make you wonder how easy it would be to build a portable device designed to record all 27Mhz data it can pull off the air for later analysis. Whilst the majority of the time it would capture useless keystrokes or harmless IM conversations, it could potentially capture bank details (although most banks now use secondary non input based authentication) or email / shopping account passwords. As if we didnt have enough to worry about with both software and hardware keyloggers already.

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