Still Here…

Posted May 26, 2014 by Tyson Key
Categories: Uncategorized

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Sorry for not updating this blog more often than I intended to, lately…

Not a great deal to report on, from a personal perspective, since I’ve mostly being trying to focus on getting through this stage of my course, and am waiting for exam results, so that I can hopefully progress onto my final year. 

Since the last time that I posted about them, my Wireshark dissectors (especially the USB CCID, and NXP PN532 ones) have seen some significant updates, thanks to the much-appreciated assistance of Michal Labedzki, and other members of the upstream Wireshark community.

This means that most of the CCID-specific USB descriptors are now dissected, and the PN532 dissector now not only supports the entire command set, but also supports the custom Host Communication Interface wrapper protocol, used by certain devices.

As a side project, I decided to start a new, L4Ka::Pistachio-based OS project, earlier this month, by branching the official GitHub repository, which as of yet still doesn’t have a name.

This one won’t initially be as ambitious as my prior, failed attempts; and I’ve already made some progress on implementing a C library, using code from the existing “libio“, various versions of BSD, and Solaris; and a shell using the existing driver for serial port, and keyboard. 

The keyboard driver is still pretty buggy (shift key support doesn’t work, for some reason); however, the serial driver works fine in QEMU, and even seems to cope with Unicode characters (the example text is a song title from a Korean band (DOZ), for the curious), without problems, provided a suitable font is available:

Image

I also started trying to implement support for ATA-based hard disk access (using a public-domain driver), and the FAT series of file systems (using Chan’s driver), but this doesn’t quite work properly, yet. 

Also, my C library implementation still has a fairly large numbers of flaws, and missing features (no file support, or streams support are probably the most glaring omissions, right now), so it’s difficult to port things to it.

Anyway, I hope that provides some explanation for my absence for so long.

Configuring a Generic Wireless LAN Bridge

Posted August 18, 2013 by Tyson Key
Categories: Everything

Tags: , , , , , , ,

Some time ago, I purchased a generic 802.11n Wireless LAN repeater, after having issues with receiving a reliable wireless connection to my ADSL residential gateway/router due to interference from neighbouring networks, and the signal propagating poorly throughout the back of the house.

I ended up buying it as a “cheap workaround”, after getting frustrated with being unable to maintain a reliable connection on my laptop, or various phones – despite trying things like switching to less congested channels (usually 9, or 13), increasing transmission power rates (at the expense of battery life); and decreasing maximum bitrates to ridiculously-levels.

Technically, the bridge is a small, embedded Linux-based device with a RealTek RTL8186 MIPS-derived system-on-chip, supporting Ethernet, and 802.11; PCI, and even PCM audio. (Which seems like overkill – but I suppose that it’s probably cheaper to design, and distribute a universal, multipurpose chipset, than it would be to produce cut-down variants).

Common complaints that buyers on Amazon had were that the firmware was buggy, the device was unreliable, and that the device’s Web-based configuration tool supposedly became inaccessible, post-configuration.

However, I found that if I ignored the supplied instructions, and attempted to configure the device by using a direct connection to my PC using Ethernet, I was able to configure it in a reliable manner that allowed for continued access to its administration server, as well as roaming throughout the house using the same SSID

Please note that the values in the screenshots are specific to my home network, and are not factory defaults.

Unfortunately, since I have discarded the packaging, I can’t provide photos of its contents – although I’m sure that they consisted of at least:

  • The device itself
  • An instruction leaflet
  • A short Ethernet cable
  • A detachable 3-pin UK mains plug

To begin with, I unpacked the product; plugged into a power outlet, and connected the Ethernet cable to my laptop.

Next, I temporarily disabled the use of my laptop’s wireless LAN chipset, using the hardware kill-switch, to ensure that requests for multiple IPv4 addresses via two hardware interfaces won’t be made.

The bridge ships configured with a DHCP server enabled by default, issuing IPv4 addresses within the 192.168.10.x range, and reserving 192.168.10.1 for itself – but we’ll change this, later.

First, navigate to the default configuration URL (http://192.168.10.1), using your preferred browser:

Next, select the “Wireless” option from the “Professional Setup” category:

Here, set the following options:

  • “Mode”: “Repeater”
  • “Network Type”: “Infrastructure”
  • “SSID of Connect to” (sic): Enter the SSID of your primary access point
  • Check the “Enable Universal Repeater Mode (Acting as AP and client simultaneouly” (sic) checkbox
  • “SSID of Extended Interface”: Enter the SSID of your primary access point again

If you have configured your primary access point to enable operation in 802.11n mode, then select either “2.4GHz (N)”, “2.4GHz (G + N)”, or “2.4GHz (B+G+N)” from the “Band” menu. Otherwise, “2.4GHz (B+G)” should deliver satisfactory performance for most WAN-based activities.

In order for seamless handover between access points using the same SSID to work well, it is then necessary to set the default 802.11 channel of your primary access point to 11. (This seems to be a hard-coded, preset value).

It may also be necessary to configure WEP, or WPA keys for your primary access point on the “Security” page; and I also recommend changing the configuration tool’s access credentials to something more secure than their default values.

After configuring these settings, the bridge will reboot automatically…

Once the bridge has rebooted, return to the “LAN Interface” page:

On this page, set the “DHCP” setting to “Client”, and apply changes. At this point, because the bridge will attempt to obtain its configuration IPv4 address from your primary access point/gateway’s DHCP server, it’d be a good idea to disconnect the Ethernet cable, and re-enable the PC’s wireless LAN interface.

Hopefully, at this point, a successful WLAN connection will have been made.

However, in order to maintain future access to the bridge’s configuration server, it is necessary to assign a static IPv4 address to its MAC address (printed on a sticker on the case – but it’ll probably also appear in system/DHCP server logs) using the configuration tool of your primary access point.

After configuring this, power-cycle the bridge, and attempt to access its configuration page via the newly-set IPv4 address. If successful, you should be presented with an authentication dialogue, and be able to see the configuration tool’s status page, as at the beginning.

Hopefully, this will be of assistance to other owners of these devices, or folks contemplating purchasing one.

WAP @ Home

Posted May 26, 2013 by Tyson Key
Categories: Everything

Tags: , , , , , , ,

Last night, I decided to install Kannel (an Open Source Wireless Application Protocol gateway), for a challenge.

It seems that installation itself was easy (just a case of downloading a snapshot archive, unpacking it, installing the libxml2-dev package from the Ubuntu repositories, and then running ./configure && make && make install to install it.

However, actually configuring it to run successfully was harder, since the “bearerbox“, and “wapbox” utilities will just unceremoniously quit with a “panic” notice, if they can’t either find their configuration file, or if it isn’t structured in a suitable manner.

I ended up copying the example configuration file from ~/kannel-snapshot/doc/examples/kannel.conf to /etc/kannel/kannel.conf, and modifying it to look like:

I also had to configure my residential gateway/router to use my laptop’s IPv4 address as a DMZ host. (Although I originally intended to just allow inbound traffic on UDP ports 9200, and 9201, for testing purposes).

After doing so, the core BearerBox utility can be invoked with bearerbox /etc/kannel/kannel.conf.

WAPBox is supposed to start automatically – however, it didn’t in my case, so I had to manually invoke
wapbox /etc/kannel/kannel.conf, in order to prevent this error:

To test to see if I could connect to the newly-installed gateway, I decided to play with the “Network Settings” view of the BlackBerry OS version of the Shazam application, since it allows for overriding of the default GPRS/WAP settings.

I ended up using the following settings (which will probably be useless for other readers, but otherwise provide a template):

APN: payandgo.o2.co.uk
Username: payandgo
Password: password
WAP Gateway IP: 95.150.51.112
WAP Port: 9201

(*) These are network WAP Settings

[Y] Enable Overrides

After selecting “Test Settings”, and waiting a while, I eventually received a packet from O2’s GPRS gateway on behalf of my handset:

Unfortunately, it seems that connections are not always successful – presumably due to either WAPBox/BearerBox configuration issues, or problems with connectivity between the GPRS gateway, my handset, and my network.

(I suspect that O2 occasionally block third-party gateway connectivity, or that the BlackBerry OS WAP stack copes badly with multiple failed connection attempts).

Connectivity problems aside, this might be a useful way of debugging/testing applications using cellular data networking on handsets without a Wi-Fi radio.

Repackaged CryptoRF/LibNFC Example Code

Posted March 30, 2013 by Tyson Key
Categories: Everything

Tags: , , , , , , , ,

Earlier, I tried to build the “NFC-CryptoRF” example code from the LibNFC Wiki, without success against LibNFC 1.7.0-rc4-9-g3584338, under Ubuntu 12.10.

Unsurprisingly, thanks to the LibNFC developers constantly changing their public APIs (for good reasons, I’m sure), said example code has succumbed to bit-rot, and only builds against obsolete versions of LibNFC.

Therefore, it seems that the only immediately obvious way for this code to be useful is to either downgrade the installed library version, or attempt to fix the hacky code to compensate for changes.

Luckily, after temporarily uninstalling my trunk version; downloading, and installing a LibNFC 1.3.4 source archive, applying the patch from a member of the LibNFC Forums to the example code, and attempting to rebuild everything, it seems that the example code works as it should.

After reinstating my modern LibNFC version; configuring 1.3.4’s build process to install to a temporary directory, copying the resulting ancient shared object file to “libnfc.so.0” in the example code directory, and creating a wrapper shell (“crf134“) script based upon the arguments passing technique mentioned here, it seems that I can now enjoy being able to use this tool, alongside more modern, “global” versions of LibNFC…

Anyway, to save others the hassle, I’ve uploaded the resulting product to Google Code.

As proof of peaceful co-existence with a more modern version of LibNFC:

Finally, in order to satisfy the terms of the (L)GPL, I have also included the original, uncompressed LibNFC 1.3.4 archive, the patched example source code, a copy of the patch, and the unpacked LibNFC directory containing both source, and 32-bit Linux binaries.

Finally, CryptoRF

Posted March 29, 2013 by Tyson Key
Categories: Everything

Tags: , , , , , , , ,

Yesterday, I finally received a package from Atmel USA containing some sample ISO/IEC14443 Type-B CryptoRF tags, after numerous failed attempts at requesting some via their sample request form.

I ordered 1 sample of the 8KB AT88SC0808CRF-MX1 variant, and 2 samples of the 4KB AT88RF04C-MX1G variant.

The 4KB tags seem to be unusually packaged, and I don’t know if it’d be safe to carefully attempt to cut the strip in half using scissors, in order to make it easier to work with each:

I was probably expecting to receive paper-mounted tags, similar to my FeliCa Lite, and MiFare UltraLight ones – but the product seems to work as advertised.

Curiously, I was able to trigger an unusual hardware glitch in the PN532 chipset, if I carefully placed the strip of 4KB tags in the reader’s field in a specific way, which manifested in the following output from nfc-list -v:

I’ve also uploaded a USB trace file demonstrating this phenomenon, here.

It seems that I’m supposed to see this, instead:

Unsurprisingly, I can’t seem to be able to reliably read either of these two, without even more careful positioning – which suggests anti-collision problems (probably since both have the same unique ID, as supplied)…

The 8KB version, and its accompanying protective packaging looks like:

(Hand not included!)

…and nfc-list -v says:

When I get time, I intend to study the datasheet, and probably play with building TAMA shell scripts, with a view to trying to write another command set dissector.

That said, I have, however tried to compile the sample code on the LibNFC wiki, without success.

Maybe someone else has succeeded in building it against the latest revisions of LibNFC?

Minor Wireshark NFC/RFID Dissector Updates

Posted March 6, 2013 by Tyson Key
Categories: Everything

Tags: , , , , , ,

Recently, I updated my FeliCa, and NXP PN532 Wireshark dissectors to support the following functionality:

PN532 dissector:

  • Support for dissection of MiFare command payloads in PN532 InDataExchange packets (bug #8291)
    • This means that command packets (but not responses) from tools such as MFOC, and the tools from LibNFC for accessing MiFare Classic, and MiFare UltraLight tokens are dissected.
  • Support for dissection of FeliCa payloads in PN532 InCommunicateThru packets (bug #8246)
    • This means that dissection of packets from almost all of an “NFC Tag Type 3” (barring NDEF payload data) tag reading session should be dissected, using the FeliCa “flavour” of notation.

FeliCa dissector:

  • Support for the FeliCa Plug system code (bug #7767)
    • This theoretically means that Sony’s new FeliCa Plug should be identified in “Polling Response” packets.
  • Update to identify commands from the full FeliCa Standard profile (bug #8243)
    • This theoretically means that commands related to enciphered reading/writing, authentication, searching for system/service codes, and requesting system information from the latest FeliCa Standard tokens should be at least identified.

I have also been trying to update Google’s dissectors to work with the latest SVN revisions of Wireshark, with mixed success. However, it seems that project has temporarily stalled – save for some brief exchanges on its mailing list, that didn’t really go anywhere.

Anyway, I remain willing to assist with that effort; and in the interim, I hope that this new functionality is useful.

Notes on installing the MDaemon BlackBerry Enterprise Server component under Windows 7

Posted January 15, 2013 by Tyson Key
Categories: Everything

Tags: , , , ,

Recently, I decided to try and install a demo version of Alt-N’s MDaemon Messaging Server for Windows, out of curiosity.

It seems that the main server component installation completes successfully – although I didn’t try to use any of the newly-installed components, immediately.

Unfortunately, installation of the optional BlackBerry Enterprise Server component fails with:

According to a page on the FalconView Wiki; and an MS KnowledgeBase article, this error relates to a permissions issue on a non-existent directory (C:\Documents and Settings\NetworkService\Application Data\Microsoft\Protect).

Under Windows 7, the equivalent directory is supposed to exist at C:\Windows\ServiceProfiles\NetworkService\AppData\
Roaming\Microsoft\Protect
– but I had to manually create it, after gaining permission to access C:\Windows\ServiceProfiles\NetworkService\.

It seems that a similar error that occurred whilst trying to install a slightly older version of MS SQL Server under Windows XP, has also been reported.

I also ended up uninstalling some existing MS SQL Server 2008 components that were supplied as with other software.

Afterwards, I re-launched the installation process, and got a little further – only to encounter another error:

It appears that rebooting Windows is the favoured workaround for this issue (that apparently relates to a (Microsoft.SqlServer.Setup.Chainer.Workflow.
ActionExecutionException
) being triggered)  – which worked for me, in this scenario, and meant that I was able to successfully use the product.

Unsurprisingly, the official product support KnowledgeBase has limited information regarding installation failures.

That said, others have reported seeing a related error under Windows XP – despite using an Administrator account; and it appears that the problem also occurred with earlier releases of MS SQL Server.

Anyway, I hope that this belated, short post is vaguely useful.


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