October « 2009 « codeblog

October 24, 2009

karmic and log rotation

Filed under: Debian,Ubuntu,Ubuntu-Server — kees @ 10:00 am

In Ubuntu’s Karmic and and Debian’s Lenny, sysklogd was replaced with rsyslog. This is fine, since rsyslog will have converted your /etc/syslog.conf to /etc/rsyslog.d/50-default.conf. However, if you modified the (maddeningly strange sysklogd-specific) log file rotation in /etc/cron.daily/sysklogd or /etc/cron.weekly/sysklogd, you’ll want to review the new (sane) /etc/logrotate.d/rsyslog. (Note also that savelog uses .0 as the first rotated file extension, and logrotate uses .1.)

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October 22, 2009

TPM as RNG

Filed under: Debian,Security,Ubuntu,Ubuntu-Server — kees @ 10:43 pm

I was reminded about some TPM coding I’d done to get random bytes from the pRNG on my TPM-enabled system from Matt Domsch’s recent post. I’m not fully convinced that the pRNG of the TPM is an appropriate source of entropy, but it does pass my simple FIPS-140-2 test.

I had to find the Intel TPM docs to figure out how to enable TPM on my system. It was under “Advanced / Peripherals”. I was expecting it under “Security”, like every other BIOS I’d seen. After that:



$ sudo apt-get install trousers tpm-tools

...

$ sudo modprobe tpm_tis

$ dmesg | grep -i tpm

[676618.167313] tpm_tis 00:07: 1.2 TPM (device-id 0xFE, rev-id 70)

$ sudo service trousers start

...

$ tpm_version

  TPM 1.2 Version Info:

  Chip Version:        1.2.2.16

  Spec Level:          2

  Errata Revision:     1

  TPM Vendor ID:       WEC

  TPM Version:         01010000

  Manufacturer Info:   57454300

$ ./tpm-getrand | hexdump -C

00000000  61 07 23 ff 71 3e 25 e8  f0 d5 de a7 a3 07 21 dc  |a.#.q>%.......!.|

I could run rngd with a named pipe, but it’d be nice to have a new driver that could run a command instead to get the next 20000 bits.

UPDATE: I’ve implemented this in rngd now.

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October 7, 2009

Larson Scanner on Arduino

Filed under: Blogging,Embedded,Ubuntu — kees @ 8:58 am

Inspired by the Larson Scanner project, I finally broke out my Arduino and ported the code from the ATtiny to the ATmega. (The Arduino IDE runs fine with openjdk-6.) I’m sure the power usage is terrible, but I wasn’t after long battery life. I wanted my very own Cylon eye.

DorkBoard running the Cylon eye

Since I was successful with porting the code and wiring up the Arduino, I figured I’d see if the tiny Arduino-clone called the “DorkBoard” would work with it too.

Later in the weekend I grabbed a AAA-battery holder and hooked that up so the eye is untethered from the USB power source. Next up, coding the pesky self-awareness.