Question for US Rules committee on AH capability within LX NAV computers?
At 06:42 09 April 2012, Max Kellermann wrote:
Paul Remde wrote:
Hi Max, Please clarify. How could it be possible to mess with the
LXNAV
LX8000, LX8080 and LX9000 firmware?
The LXNav products are just Linux PCs, and it is easy to install a
customized firmware.
The LXNav firmware update comes with a shell script that gets executed
on the LX8000 (autorun.sh), and that would be the easiest hook of all
to get custom code in.
Once you have your custom AH code in, you can easily run it as a Linux
daemon, overlaying its data on the Linux frame buffer (/dev/fb0).
To detect such a hack, you would need to inspect all of the LX8000's
memory, it would be as hard as detecting a computer virus or a
rootkit. In other words: practically impossible for a competition to
do.
(The same is true for any other flight computer, the LX8000 is just an
example, because my club has one and I know well how the firmware
works)
Seriously this identifies the problem with this sort of rule: it is
impossible to enforce. A rule that cannot be enforced, like a law that is
not enforced is seldom complied with even by "honest" people. Pandora is
out of the box, technology has overtaken the ability to detect the fitting
or use of such an instrument. The FAI is as out of touch with reality on
this as they are with flight recorders, hacking the code for IGC files is
now so simple that it is no longer secure and it matters not how long the
key is. (The private key is in every flight recorder produced so all you
have to so is break into the software to get it, who wants to try and
compute it from the public key?)
When making rules one of the primary considerations should be "can it be
enforced"? Far to often the answer is no but ignorant people still make the
rule.
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