SELinux on Android

Posted Aug 31, 2014 11:30 UTC (Sun) by dlang (guest, #313)
In reply to: SELinux on Android by yaap
Parent article: SELinux on Android

Harald Welte has deployed an open source cell site several times over recent years, so it's possible to do it from a technical point of view.

As for the problems of people tweaking things, turning up power and so on was done before OpenWRT was available, game console hacks show that you don't need open source to tamper with things (in fact, many of the hacks to the consoles are far more sophisticated and complex than what would be needed if the source was available and could be installed)

As software radios become more common and cheaper (such as the $30 Baofeng uv-5r series that can transmit 136-174,400-480MHZ) the technical capability for people to stomp all over the radio spectrum becomes easier, but contrary to the fears of the 'communications professionals" (very similar to what you express), it has not resulted in mass jamming.

It's already possible to buy cellular repeaters (I have done so), which could also be misused to cause all sorts of problems.

Yes, there will always be people who are going to cause problems, outlawing things doesn't stop them, and frequently doesn't even slow them down (see C.B. amplifiers for one example)

I also think that it's inevitable, it will take a while still, but as it becomes cheaper to implement the radio protocol in more general purpose systems for less money, you will see people starting to do exactly that. You will also see the industry trying to block it and continuing to sell much more expensive versions of the equipment. There will be times when that expensive version is needed (usually in the middle of the big cities where there are more radios per square foot), but there is also a huge area where it will be 'good enough' and not cause noticeable problems.

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SELinux on Android

Posted Aug 31, 2014 12:06 UTC (Sun) by yaap (subscriber, #71398) [Link]

I mostly agree with what you say, with comments.

Yes, there has been no mass jamming so far. But:

1) people playing with RF devices are a small minority;

2) it's very easy to underestimate the impact to others. When there's a problem and you shoot yourself in the foot, well you'll definitely notice it and then fix the problem. When you create a problem only for others it's a very different situation: it's easy to overlook. More so because the other people suffering from the issue typically won't understand the root cause or be able to trace the issue to its cause. They'll usually blame their device or network, and move along. This create a strong bias toward underestimating the created issues.

Because of the later, my recommendation to people playing with radio systems: have fun (I certainly can understand the interest ;), but please please be cautious for others. Try to be paranoid on what could go wrong before moving to the field.

An example: the SDR systems typically have no RF filtering, because there is no configurable filters of sufficient performance (yet). Without filter a device will create a lot of interference in surrounding frequencies and possibly jam other, unrelated systems. Not a problem in the lab at very low power, but you want to have proper filtering in the field.