Reverse Engineering Firmware : Linksys WAG120N | Hacker News Reader

Reverse Engineering Firmware : Linksys WAG120N

devttys0.com

101 pointspeppaayaa22 comments

I use GOLEM, a disassembler that allowed annotating the resulting source (adding lables and comments) and re-running the disassembler for ever-more-informative disassembly. It was also script-based so it could disassemble any machine code (if you were patient enough to write up all the patterns). It could also recognize complex sequences and produce pseudo-instructions e.g. Loop, TestAndBranch etc.

Anyway, not really related, this article is about detecting linux's signature and identifying the kernel, but it brings back old times.

Do you have a link to GOLEM? Google didn't give me anything useful.

Internal project at company. I'll see if I can get a copy somehow.

Relatedly: is there a good home wireless router on the market today? Hardware & firmware revs have made googling for an answer somewhat difficult: I figure here I'm likely to find a good replacement for my less-than-stellar WRT54G.

The very best broadcom-based router (for maximum homebrew capabilities) is definitely the Asus WL-500G Premium V2.

I was introduced to it by the developers of DD-WRT, and now use it w/ Tomato USB.

Its advantages over all the competition is the far superior hardware specs in terms of speed and memory, the reliable construction, the two antennas, and the excellent signal range. It is far more expensive (I think I got it around 80 bucks 4 years ago?) but it's still alive and ticking now and definitely worth it!

Reviewed: http://www.tweaktown.com/reviews/2700/asus_wl_500g_premium_v...

If you can't afford that one, I've had excellent results with the Buffalo WHR-HP-G54. I have several of them, useful for doing mesh networking so I don't have to go laying cables all over rented houses.

You can just about run OpenVPN on it as well.

It also has an internal serial port, and people have managed to power it on batteries and suchlike fun things.

Do yourself a favor and get a Picostation 2 from Ubiquiti [1], it's a hacker's dream. They're $59 over at netgate [2].

* The Picostation 2 has 8MB of flash and 32MB of RAM, which is enough to install and run quite a few interesting things beyond just the kernel: asterisk, openvpn, python, perl etc. For comparison, my WRT54GL only has 2MB of flash and the kernel is 1.7MB -- I run djbdns and tcpdump on it and that's about all I've got room for.

* The Picostation 2 ships with an open firmware, AirOS Linux. OpenWRT also has prebuilt images for the Picostation 2 [3]. There's something like 1000 OpenWRT packages available for quick binary install via opkg, see the list here [4].

* Weatherproof enclosure and Power over Ethernet. Comes with a PoE injector.

* Standard replaceable RP-SMA external antenna.

[1] http://www.ubnt.com/picostation

[2] http://store.netgate.com/Ubiquiti-PicoStation2-80211bg-100mW...

[3] http://downloads.openwrt.org/backfire/10.03.1-rc4/atheros/

[4] http://downloads.openwrt.org/backfire/10.03.1-rc4/atheros/pa...

If you make heavy use of your internet connection, use VPN or need more flexibility at home then I'd highly recommend pfsense [0]. Its a routing / security appliance software based on freeBSD. You an run it on almost any old machine with enough network ports for what you want to do. Alternatively you can install it on a cheap Atom board, Jetway makes several and offers up to 4 gigabit NICs on them.

I'm using a Atom 330, 1GB of ram, compact flash hard drive, 4 1-Gbit ports. Cost about $250 i think total and can happily handle tens of thousands of connections and maintains 30Mbps openVPN throughput (limit of my connection). Most importantly I haven't had to reboot it or even think about it 8 months.

For the wireless side of things, you can get a wifi card for the pfsense box and run in as an AP or really any old wifi router will do. I've actually found that most are quite stable _after_ you turn off all routing/firewall functionality and use then as a pure wifi AP.

[0] http://www.pfsense.org/

I was in a similar position a few months ago. I settled on a Netgear WNDR3700 for the following reasons:

* cheap - $79 refurbed @ TigerDirect - http://www.tigerdirect.com/applications/SearchTools/item-det...;

* gigabit ports

* lots of ram - 64MB

* lots of flash - 8MB

* expandability - USB for more storage

* 80211.N support with 2.4GHz and 5Ghz bands

* popularity - well supported by OpenWRT (I'm a former DD-WRT'er and like OpenWRT so much more)

So far extremely stable running OpenWRT trunk and a lot of fun to tinker with :-)

I enjoy my Buffalo WZR-HP-G300NH . I had a WRT54G as well, but then I got an internet connection faster than it could handle (it became the bottleneck). Comes stock with (a modified version of) DD-WRT (and flashing your own is supported).

http://www.dd-wrt.com/wiki/index.php/Buffalo_WZR-HP-G300NH

What is wrong with your WRT54G? I have a WRT54GL with DD-WRT on it and have had no problems.

They're usually pretty stable, but they are lacking in features compared to current routers.

My WRT54GL has been deteriorating, with uptimes peaking at about one week, and two broken ethernet ports. I recently upgraded to a Netgear WNDR3700, which lets me escape the overcrowded 2.4Ghz spectrum (none of my neighbors use the 5Ghz spectrum, whereas I can pick up about 15 different APs on the 2.4Ghz channels), and helps switch my wired network over to gigabit ethernet (which all but one of my computers now support). The new router also has about 4 times more RAM, Flash, and CPU power, so it can run a wider range of software. At some point I'll probably also start using it as a file/backup server with a USB hard drive.

I've bought multiple WRT54GLs because of the aftermarket firmware available for that model, but really it's quite old these days and there are comparably priced alternatives with much better specs. If you're getting a new router, you should definitely look into something more recent; the WRT54GL is just dated now. My home WRT54GL finally crapped out after ~five years earlier in 2011. I bought a Buffalo WZR-HP-G300NH and loaded up openwrt and I'm satisfied with it (though I wish I would have known to put trunk openwrt on first; stable is not maintained very well, developers hint strongly at just using trunk).

I have purchased no less than five (possibly six) of them over the last eight years. After the third device failure, it ceases to be an anecdote and starts to become a trend. I would guess that the median lifespan of a WRT54G is likely on the order of 18-24 months.

Perhaps I was lucky but I have not had these problems. I have a wrt54g v2 from many years ago still chugging along happily. However, as others have mentioned there are modern routers with a sub $100 price that give you much more bang for your buck. Wrt54's were great for their time but I would consider them a bit dated if you are looking to purchase a router today.

At the moment maybe nothing but many older routers simply don't have the horsepower to keep up with faster internet connections. (say beyond 40-50Mbit/sec)

WRT54G with Tomato here, and loving it.

I use Linksys E3000 with DD-WRT and it has been absolutely great for me.

Mine was great until I had too many concurrent connections, which involved a crash and a wipe of its configuration...

May be you needed to reduce the TCP & UDP timeouts and update to latest v16785 SP2 of DD-WRT. Mine runs months without a reboot and I have half a dozen connected devices with infrequent bittorrenting going on.

it's unreal that in 2011 these things are still junk.

This is really neat.

I'd be also interested in the reverse: modding the firmware, packing it up and flashing it onto the device.

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