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Hard, Not Soft, Kill Switches

puri.sm

61–70 of 82 posts

Re: Hard, Not Soft, Kill Switches

#63
post #8

Ok, maybe I've been doing too much hardware development and more tinkering than the average guy, but this part here, to me, sounds way overblown: > As you can see, it is not a trivial matter to > manufacture these HKSes. A lot of research and > hard work went into the effort. I mean, compared to all the other things one has to get right to design a laptop computer, switching these few signals is indeed very, very tri…

Especially since all of these peripherals are COMPLETELY modular for desktop form factors, since you could theoretically buy motherboards without these optional hardware features, and purchase them as completely separate devices, implying that they are assuredly unpluggable, and therefore, without question "switch-off-able" in very real terms.

So, yeah, why all the solder and "chip" modifications?

Re: Hard, Not Soft, Kill Switches

#64
The frustrating thing about the situation with the NSA and other state actors is that any security product actually seems like it makes one more of a target.

The laptop that security conscious people buy is a more logical target than the laptop the random consumer buys.

Buying a better rated consumer laptop for cash in person, loading your favorite secure OS and locking it down as well as possible seems like a better path than buying anything label "secure" with your credit card attached to your identifying information.

Re: Hard, Not Soft, Kill Switches

#65
post #11

Earlier quoted context omitted.

No, that's probably just by convention. If it's strictly an input then both directions are just the same in terms of safety. It's just sometimes more convenient to only pull things down or up and have a resistor provide the opposite pullup/pulldown current. Maybe it was chosen because the "high" voltage isn't specified and the standard might say: "Pull down to GND to activate, leave open to keep card off." Then you d…

This would work better if the switch worked as you described - close a circuit to GND to turn the card on, leave the circuit open to turn the card off. If the wires to the switch fail then the card fails on.

Not necessarily. An open wire doesn't mean 0 volts -- it is whatever the input of the gate floats to. There is no standard -- it depends if the manufacturer put a weak pull-up or pull-down into the chip, or if they have an active termination that will pull to either end. Or if the gate isn't designed any particular way, it could be subject to how well doped the transistors of that particular chip turned out. Being open also means it is subject to noise from adjacent signals, so it could be random that way, too.

Re: Hard, Not Soft, Kill Switches

#66
post #29

It would be cool if there was a fail safe switch that nuked the hard drive with microwaves or something crazy like that when it was pressed. That would be one laptop I'd buy.

If you're going to go that route, you want an encrypted hard drive whose keys can be destroyed at a moment's notice. I believe that's off-the-shelf tech now, but I'm not sure where to point you at it.

It would also have to have no recovery mechanism, otherwise that could be (ab)used to recover data after nuke.

Re: Hard, Not Soft, Kill Switches

#67
post #60
post #49

Earlier quoted context omitted.

This is a great point! And the ME (Management Engine [1]) rears its ugly head. Even Google Chromebooks with a "write protect screw" do not actually wire the write protect screw to the hardware "disable writes" signal on the flash. And it's because the ME is continuously writing stuff to its region of the flash and the ME cannot be disabled. Such a security fail! Assuming these guys succeed the ME ceases to become a p…

Chromebooks only write protect half of the flash, the ME partition is in the other half.

As long as you mean "write protect" in quotes, because the write protection is handled by circuitry outside the flash chip itself which then means that to be sure your flash is _actually_ protected you have to verify that additional stuff.

Re: Hard, Not Soft, Kill Switches

#68
post #8

Ok, maybe I've been doing too much hardware development and more tinkering than the average guy, but this part here, to me, sounds way overblown: > As you can see, it is not a trivial matter to > manufacture these HKSes. A lot of research and > hard work went into the effort. I mean, compared to all the other things one has to get right to design a laptop computer, switching these few signals is indeed very, very tri…

To me it sounds like a practical decision. Go buy a USB wifi adaptor and plug and unplug it 100 times. Then tell me if the adaptor works correctly after that; the kernel driver is probably in some undefined state now.

The reality is that the chip/firmware/driver combination is tested by turning the power on once and then making it pass a few benchmarks that reviewers like. Doing something new and exciting may or may not work.

Certainly, some drivers are way better than others (ath9k is pretty good), but I imagine they tested the power up/power down method, noted that the kernel panics 1 time in 10, and decided nobody would buy their product if they implemented it that way.

Re: Hard, Not Soft, Kill Switches

#69

Great! Small point though, i would be in favour of a separate Bluetooth and Wifi kill switch. EDIT: They use i5 and i7 processors, which IIRC use black-box Intel microcode... Also, i wonder if they support Libreboot? My apologies if it turns out i cannot read. Otherwise they look quite nice. I'm excited to see more "alternatives" in the "free as in liberty" laptop space. EDIT 2: Some more information here: https://ww…

> EDIT: They use i5 and i7 processors, which IIRC use black-box Intel microcode... Also, i wonder if they support Libreboot? My apologies if it turns out i cannot read. Otherwise they look quite nice. I'm excited to see more "alternatives" in the "free as in liberty" laptop space. They are going to use coreboot, which is free but includes some binary blobs from Intel. I don't think you can boot any modern x86 without…

They can but nobody will put in the work or money:

http://www.gaisler.com/index.php/products/ipcores/soclibrary

You get an open ISA w/ Open Firmware w/ open HW implementation under GPL that you can fab wherever, including MPW runs that cut costs. Or you can just buy the one's he sells which go up to 4 cores now. Developers porting browsers, flash, servers, whatever can use regular development boards to get most of it done. Gaisler and SPARC have been best option to jump-start open HW/SW movement for a long time. Just not utilized.

A Transmeta approach could be used with underlying RISC core for x86 emulation. Wouldn't be core i7 speed or anything but it could be acceptable. China's MIPS-based Loongson does this.

Re: Hard, Not Soft, Kill Switches

#70
post #59

Great! Small point though, i would be in favour of a separate Bluetooth and Wifi kill switch. EDIT: They use i5 and i7 processors, which IIRC use black-box Intel microcode... Also, i wonder if they support Libreboot? My apologies if it turns out i cannot read. Otherwise they look quite nice. I'm excited to see more "alternatives" in the "free as in liberty" laptop space. EDIT 2: Some more information here: https://ww…

I don't really feel like the librem laptops offer much value when built using a processor with IME. It's offering a mostly open source laptop, but still has a massive gaping backdoor for someone to log your every keystroke and get every bit of your data - even if the laptop is off or your harddrive is encrypted (source: http://libreboot.org/faq/#intel ) I am more excited in the continued development of the Novena lap…

Yeah, the discussions get funnier when you see people speculating about Intel backdoors and ask yourself "Did everyone forget about Intel AMT?" Whether it's on or not, the functionality is probably in every chip in the family and maybe others to cut NRE costs.

Most open, security-focused laptop with the most closed, backdoored processor. It's funny shit.

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