[sf-lug] 2019-08-04 meeting notes, about WRT54G* 3rd party router firmware

Mon Aug 5 10:16:14 PDT 2019

Bobbie Sellers <bliss-sf4ever at dslextreme.com> wrote in [01]
> Aaron came in with a couple of routers and took one or more away
> including I think the book on programming them.
>
> About 12:20 Jim Stockford showed up.

Not at all to Steal any of Charlie's Fire in his discussion of his vast IT 
experience "of over 35 years in Silicon valley" (see reference [02]), but 
I'd add that there were also a few mini-discussions regarding the WRT54G* 
routers (see reference [03]) that John S graciously donated to several of 
us meeting participants.
IIRC, the three WRT54G* routers models were
- the WRT54GLv1.1 (see its full WikiDevi description at reference [04])
- the WRT54Gv2.2 (see its full WikiDevi description at reference [05])
- the WRT54Gv3.1 (see its full WikiDevi description at reference [06])

I took the WRT54GLv1.1 without an included power adapter, Jim S took the 
WRT54Gv2.2 _with_ its included power adapter, and Adell (if that's the 
correct spelling of his name) took the WRT54Gv3.1 also with its included 
power adapter.  Going back to the previous mailing-list threads of about a 
year-and-a-third ago of [07] and [08] concerning various consumer-router 
firmware, all three of these WRT54G* routers had 4 MiB flash and 16 MiB 
RAM.  A practical import of these routers' flash and RAM limitations is 
that current versions of OpenWRT may not function adequately on these 
routers as per the OpenWrt's ominous-sounding "4/32 warning" in reference 
[09].
Directly quoting that OpenWRT 4/32 warning page....
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Every operating system requires

     1. Sufficient Flash to accommodate firmware image
     2. Sufficient RAM for stable operation

((!)) Devices with 4MB flash and/or 32MB ram will work but they will be 
very limited (usually they can't install or run additional packages) 
because they have low RAM and flash space. Consider this when choosing a 
device to buy, or when deciding to flash OpenWrt on your device because it 
is listed as supported.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Also see the 4/32 warning page's sections "Usability issues;Insufficient 
RAM for stable operation" and "Extensibility issues;Barely enough Flash to 
accommodate OpenWrt firmware image".

The point from OpenWrt's 4/32 warning is that current and future versions 
of its firmware are discouraged for use on WRT54G* routers such as these 
which have 4 MiB flash and 16 MiB RAM, at least for most users anyway. 
Better firmware for these routers, subjectively-speaking, could possibly 
be DD-WRT and Tomato firmware, which according to at least references 
[10],[11] and [12] (besides within the routers' aforementioned WikiDevi 
descriptions at [04],[05],[06]) are all well-supported on these WRT54G* 
routers.

OTOH, Rick M wrote within his prior posting at [13]:

> Remember:  Whether vulnerabiities in old software matters depends
> in part on what features are enabled in the local installation.
> E.g., I routinely skim-read CVEs about kernel bugs and judge them
> to be irrelevant to my system because they're flaws in
> drivers/subsystems not present on my systems.
> While I doubt any 2.4.x kernels are still safe today, I'll bet
> many 2.6.x kernels are, particularly ones for which the local admin
> has locked down what is enabled (and more so ones compiled locally
> to build only what is needed, though few admins bother to do so any
> more).

And DD-WRT's K26 Build Supported Router List for its 2.6.x kernel firmware 
in reference [14] specifically _excludes_ all three of these WRT54G* 
routers. Which possibly/probably means that _few_ of DD-WRT's 2.4.x 
kernels in its K24 builds are deemed to be "still safe today" :-\

So for most users, this could very well be a tradeoff between having to 
use older OpenWrt firmware that is just able to fit on these WRT54G* 
routers vs. using one of DD-WRT's potentially "unsafe" K24 builds.

Further router firmware questions remain.
E.g.,
- How far back does one have to go to obtain sufficient OpenWrt firmware 
for these routers?
- Given the OpenWrt Release Archive list of [15], will LEDE 17.01.x 
firmware function appropriately on these three WRT54G* routers? How about 
the same for either Chaos Calmer 15.05x, Barrier Breaker 14.07, Attitude 
Adjustment 12.09, Backfire 10.03x, or even earlier??
- If a DD-WRT K24 build (with its mandatory 2.4.x kernel) is preferable, 
then which numbered build is best, even it's not necessarily the latest 
and highest-numbered build?
- And which specific DD-WRT V24_pre_sp2 K24 build listed within the chart 
at reference [16] is best for a particular WRT54G* device, from the below 
handful of options with their numerous pick-n-choose set of features??
-- dd-wrt.v24_micro, a.k.a. "Micro"
-- dd-wrt.v24_mini, a.k.a. "Mini"
-- dd-wrt.v24_std, a.k.a. "STD"
-- dd-wrt.v24_voip, a.k.a. "VOIP"
-- dd-wrt.v24_vpn, a.k.a. "VPN"

Rick M, Michael P, Bobbie S, and anyone else reading are all welcome to 
jump in here with your opinions, suggestions, background info, website 
referrals, .... etcetera.

-A

==========================================
REFERENCES:
==========================================
[01]http://linuxmafia.com/pipermail/sf-lug/2019q3/014293.html
[02]https://www.openrefactory.com/
[03]http://linuxmafia.com/pipermail/sf-lug/2019q3/014284.html
[04]https://wikidevi.com/wiki/Linksys_WRT54GL_v1.1
[05]https://wikidevi.com/wiki/Linksys_WRT54G_v2.2
[06]https://wikidevi.com/wiki/Linksys_WRT54G_v3.1
[07]http://linuxmafia.com/pipermail/sf-lug/2018q2/013161.html
[08]http://linuxmafia.com/pipermail/sf-lug/2018q2/013163.html
[09]https://openwrt.org/supported_devices/432_warning
[10]https://wiki.dd-wrt.com/wiki/index.php/Linksys_WRT54G/GL/GS/GX
[11]https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=51486
[12]https://wikidevi.com/wiki/List_of_Tomato_firmware_supported_devices
[13]http://linuxmafia.com/pipermail/sf-lug/2018q2/013153.html
[14]https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=63757
[15]https://downloads.openwrt.org/
[16]https://forum.dd-wrt.com/wiki/index.php/What_is_DD-WRT%3F#File_Versions
==========================================

aaronco36 at sdf.org
---