Category Archives: Linux

Ubiquiti’s mPower ships with ancient Dropbear 0.51 and no forced command support

Bane of all hardware products — software updates.

The exciting mPower and mPower PRO power strips that I am otherwise happy with are, even in the latest firmware version, sadly shipping with an ancient version of Dropbear. This means no command restriction in authorized_keys file.

sigh

In hopes that their firmware release engineering processes are such that swapping one Dropbear version for another will not take too much effort, I’ve opted to file a support request, upon which I was directed to post a request on the forums.

Sadly, I don’t think I could even work around this with multiuser support and putting together a .profile, given that this device is not really built for multiuser use. (That is, it seems to have one user, root, which may or may not be renamed. For example, in /etc/passwd, uid 0 on my devices is called ivucica.)

If they do, hopefully they opt for the latest release, as apparently 0.52 and later had security vulnerabilities exactly with command= restriction.

Gajim causing kernel lockup on startup

Specifically, Gajim’s use of python-crypto (or something similar) has been causing the kernel to lock up for me, months ago. 100% repro rate: I would launch Gajim, and kernel would lock up on the relevant core even before Gajim showed the first window.

Trying to pinpoint it using strace, it was actually an attempt to read /proc/brcm_monitor0. I have no idea why it would try to read it, but once it did, kernel would lock up on one CPU core (seen by examining dmesg), and slowly other CPU cores would follow.

Given that I don’t actually need the Broadcom wireless card on my desktop machine (at least ever since I wired up my room), I’ve just blacklisted the wl module:

$ cat /etc/modprobe.d/blacklist-IVUCICA.conf
blacklist wl