5 ms·

In this day and age, no computer is just a CPU. Each radio effectively have their own CPU and accompanying firmware. The phone OS is as much in control of that

In this day and age, no computer is just a CPU. Each radio effectively have their own CPU and accompanying firmware. The phone OS is as much in control of that radio (at best) as your laptop is in control of the ISP router.

dewster 10y ago
Surely the main processor could query the sub processors for relevant info like current state? if this isn't possible then the HW/SW world of phones makes no sense.
- digi_owl 10y ago
  And if the subprocessor is compromised, what is the chance that it would not lie? When it comes to these things there is no such thing as "too paranoid" (sadly).
  - dewster 10y ago
    HW & SW just happens in the middle of the night by elves? Mistakes were made? For a tech board I expect a bit more ownership of the problem here. This is OUR domain and we should act like it.
    - beagle3 10y ago
      Who are these "us" you are talking about (as in, "OUR domain", "we should")?
      - dewster 10y ago
        HW & SW engineers (I'm one, I assumed many or most here are as well).
- yourad_io 10y ago
  The point is that there is such complexity in your average smartphone, that strictly enforcing radio silence with software from within is practically impossible. Let's forget everything aside from GSM for a moment. The GSM/LTE/whatever radio runs very closed source firmware. This communicates with the very closed source CPU and other subsystems, controlled by the very closed source OS. On top of that you run various other closed source apps, opening potentially malicious documents and browsing potentially malicious links. In theory nothing goes wrong. When you hit 'airplane mode', the OS tells the radios to STFU. In practice, anything could go wrong - maliciously or not. Your phone could have been "jailbroken" without your knowledge by a 0-day exploit, effectively negating the OS security. Once the bad guys are in your OS, they may as well update your baseband firmware to do whatever they want. Or any of the other firmware/drivers/ICs that they are able to access. Or CPU microcodes. Anything. Ideally you would have a phone with a physical switch, powering off all radios. Not politely instructing them to please cease functioning, but actually power them the f... off. This almost never happens. I have a hardware switch on my laptop - this doesn't actually cut the power to the wireless radios. If/when the firmware is compromised, it is as useless as the Wifi LED indicators. So, great, you'll say - implement that rather than build a whole new system to babysit your smartphone stack. Make a hardware switch that powers off all radio subsystems. Even if that were possible, your iPhone would not like a subsystem disappearing from existence. It isn't designed to handle that contingency and will surely fail in spectacular ways. Hence, tapping into debug ports/buses/etc and trying to monitor traffic that way. The analog way[1] may make more sense, but usability would probably be restricted. I'm fairly certain Snowden has heard of faraday cages. [1] https://www.amazon.com/FawkesBOX-Smart-phone-Faraday-Cage/dp/B00QQUQTV2 https://www.amazon.com/FawkesBOX-Smart-phone-Faraday-Cage/dp...
  - dewster 10y ago
    > The point is that there is such complexity in your average smartphone, that strictly enforcing radio silence with software from within is practically impossible. Change is never impossible for something we ourselves design and manufacture. >The GSM/LTE/whatever radio runs very closed source firmware. This seems like a problem that could be fixed. >Your phone could have been "jailbroken" without your knowledge by a 0-day exploit, effectively negating the OS security. Probably sounds quaint, but run SW from a ROM. >Make a hardware switch that powers off all radio subsystems. Even if that were possible, your iPhone would not like a subsystem disappearing from existence. It isn't designed to handle that contingency and will surely fail in spectacular ways. You seem to be saying that the iPhone SW can't be altered to tolerate the disappearance of a subsystem, I just don't believe this is true. It's a poor excuse to do nothing. If humans are incapable of writing secure SW, then put in one or more physical switches that powers down all transmitters, and write SW that can adapt to this. Don't tell me that's impossible or even all that difficult.

dewster 10y ago

Surely the main processor could query the sub processors for relevant info like current state? if this isn't possible then the HW/SW world of phones makes no sense.

digi_owl 10y ago
And if the subprocessor is compromised, what is the chance that it would not lie? When it comes to these things there is no such thing as "too paranoid" (sadly).
- dewster 10y ago
  HW & SW just happens in the middle of the night by elves? Mistakes were made? For a tech board I expect a bit more ownership of the problem here. This is OUR domain and we should act like it.
  - beagle3 10y ago
    Who are these "us" you are talking about (as in, "OUR domain", "we should")?
    - dewster 10y ago
      HW & SW engineers (I'm one, I assumed many or most here are as well).
yourad_io 10y ago
The point is that there is such complexity in your average smartphone, that strictly enforcing radio silence with software from within is practically impossible. Let's forget everything aside from GSM for a moment. The GSM/LTE/whatever radio runs very closed source firmware. This communicates with the very closed source CPU and other subsystems, controlled by the very closed source OS. On top of that you run various other closed source apps, opening potentially malicious documents and browsing potentially malicious links. In theory nothing goes wrong. When you hit 'airplane mode', the OS tells the radios to STFU. In practice, anything could go wrong - maliciously or not. Your phone could have been "jailbroken" without your knowledge by a 0-day exploit, effectively negating the OS security. Once the bad guys are in your OS, they may as well update your baseband firmware to do whatever they want. Or any of the other firmware/drivers/ICs that they are able to access. Or CPU microcodes. Anything. Ideally you would have a phone with a physical switch, powering off all radios. Not politely instructing them to please cease functioning, but actually power them the f... off. This almost never happens. I have a hardware switch on my laptop - this doesn't actually cut the power to the wireless radios. If/when the firmware is compromised, it is as useless as the Wifi LED indicators. So, great, you'll say - implement that rather than build a whole new system to babysit your smartphone stack. Make a hardware switch that powers off all radio subsystems. Even if that were possible, your iPhone would not like a subsystem disappearing from existence. It isn't designed to handle that contingency and will surely fail in spectacular ways. Hence, tapping into debug ports/buses/etc and trying to monitor traffic that way. The analog way[1] may make more sense, but usability would probably be restricted. I'm fairly certain Snowden has heard of faraday cages. [1] https://www.amazon.com/FawkesBOX-Smart-phone-Faraday-Cage/dp/B00QQUQTV2 https://www.amazon.com/FawkesBOX-Smart-phone-Faraday-Cage/dp...
- dewster 10y ago
  > The point is that there is such complexity in your average smartphone, that strictly enforcing radio silence with software from within is practically impossible. Change is never impossible for something we ourselves design and manufacture. >The GSM/LTE/whatever radio runs very closed source firmware. This seems like a problem that could be fixed. >Your phone could have been "jailbroken" without your knowledge by a 0-day exploit, effectively negating the OS security. Probably sounds quaint, but run SW from a ROM. >Make a hardware switch that powers off all radio subsystems. Even if that were possible, your iPhone would not like a subsystem disappearing from existence. It isn't designed to handle that contingency and will surely fail in spectacular ways. You seem to be saying that the iPhone SW can't be altered to tolerate the disappearance of a subsystem, I just don't believe this is true. It's a poor excuse to do nothing. If humans are incapable of writing secure SW, then put in one or more physical switches that powers down all transmitters, and write SW that can adapt to this. Don't tell me that's impossible or even all that difficult.