Exploring The Ubiquiti AP Firmware

There is a small issue that I noticed in the UAP-AC-PRO firmware images — I’ve posted this issue on the community forums and also filed a tracker report. It’s a shell script (or incomplete image) type of error depending on how you look at it but if you SSH into the AP you’ll notice this trace file:

home-BZ.v4.3.28# cat /tmp/rc.txt
+ [ -e /usr/etc/rc.postconf ]
+ [ -e /etc/ltecfg/lteUpgradeSierraWireless.sh ]
+ init -q
+ bgnd -r garp -- /sbin/garp -s 2
ERROR: bgnd: EXEC FAILED! Executable: /sbin/garp

If you check to see where this binary executable exists on the firmware image itself, it turns out it is indeed missing:

# echo $PATH ; which garp ; ls -l /sbin/garp
ls: /sbin/garp: No such file or directory

And if you look at which shell script is responsible for this error message (it’s an rc startup script):

# grep -in '' /etc/rc.d/rc
92:start() {
93:	# assumes a good starting point (module unloaded, processes stopped)
95:	# update running config
194:	# done.
195:	bgnd -r garp -- /sbin/garp -s 2 &
196:	# NOTE: we didn't set the LED here. instead, we rely on the management agent (mcad)
197:	# to call syswrapper.sh:set-ready
215:	# make new /etc/inittab takes effect
216:	init -q

Either the image needs to include this referenced binary or the shell script needs extra logic to determine when to call the gratuitous ARP command successfully!

Exploring The Ubiquiti AP Firmware

One thought on “Exploring The Ubiquiti AP Firmware

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s