Entropy Key not working on Ubuntu Server 12.04 LTS

Joshua Newton newton.joshua.x at gmail.com
Tue May 8 01:20:04 BST 2012

Unfortunately, I don't have a great deal to add to that. The Entropy Key 
in question works perfectly on an x86 Gentoo machine running a 2.33GHz 
Conroe C2D. The machine is being replaced with amd64 Ubuntu 12.04 Server 
LTS with a 3.3GHz Sandy Bridge Core-i5 (2500).

The software difference is 1.14 on Gentoo vs. 1.15 on the new Ubuntu 
machine. Plugging the Key back into the Gentoo machine and running 
ekey-rekey works immediately whereas ekey-rekey hangs after being given 
the master key.[1] ekey-setkey always reports that "The key given did 
not decode to the correct length. (12/32)" when given the identical 
master key.

And ekeyd appears to work correctly (appears in ekeydctl list and 
propagates the kernel entropy pool) on the Gentoo machine, but does not 
work at all (does not even appear in ekeydctl list) on the new machine. 
Both machines register the key as /dev/ttyACM0.

Running ekeyd with "Daemonise(false)" on the new machine produces no 
output at all.

Finally, I've tried running "/etc/init.d/apparmor teardown" to kill off 
all AppArmor profiles that might in some way prevent ekeyd from working.

ETA: If given the master key after the machine is powered down cold, 
ekey-rekey appears to work, so long as ekeyd is *not* allowed to run at 
start. However, ekeyd still does not work.

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