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Previous discussion of XNU/Secure Boot on Lightning video adapters (2013) : https://news.ycombinator.com/item?id=5307781 https://news.ycombinator.com/item?id=53

by bri3d 7y ago

Previous discussion of XNU/Secure Boot on Lightning video adapters (2013) : https://news.ycombinator.com/item?id=5307781 https://news.ycombinator.com/item?id=5307781 . This thread has some new information and maybe people will start playing with these more eventually.

throwaway3627 7y ago
Makes you wonder if some rogue device/adapter/charger could deliver malware (sploit/trickery) to it before or after it's booted from the host.
- reaperducer 7y ago
  Unlikely since the Apple adapter contains no software. The firmware is loaded by the host device when it's plugged in.
  - CGamesPlay 7y ago
    Doesn’t that mean that a rogue device that did contain software and ignored the incoming packet might actually be trusted by the host device when it shouldn’t be? The twitter thread did say the firmware payload contained no personalization (like encryption keys, perhaps).
    - saagarjha 7y ago
      > The twitter thread did say the firmware payload contained no personalization (like encryption keys, perhaps). To be clear, this just means that the firmware isn't tied to a specific device via the normal ECID/nonce pair like a normal iOS update is.
citrusui 7y ago
For more context, check out this comment on the Panic Blog: https://panic.com/blog/the-lightning-digital-av-adapter-surprise/#comment-16841 https://panic.com/blog/the-lightning-digital-av-adapter-surp...
- stefan_ 7y ago
  Don't drink the kool-aid. An adapter that destructively compresses the signal is an unexpected and unmitigated disaster, not some cool quirk of Lightning that makes "the host not care what is hanging off it". The real reason this abomination exists is because as recently as 2018, Apple is selling products with a connector that has the equivalent bandwidth of USB 2, not even close to transporting a single 1080p video signal.
  - lloeki 7y ago
    It’s destructive, and it probably also introduces a quite decent amount of latency.
  - bscphil 7y ago
    Yes - this is really quite astonishing. I imagine any video professional would be horrified to learn that their CABLES were recompressing their video. There's never an acceptable reason for that it's really amazing I haven't heard about it before.
- tinus_hn 7y ago
  I wonder what they use for the demos at WWDC.

by bri3d 7y ago

throwaway3627 7y ago

Makes you wonder if some rogue device/adapter/charger could deliver malware (sploit/trickery) to it before or after it's booted from the host.

reaperducer 7y ago
Unlikely since the Apple adapter contains no software. The firmware is loaded by the host device when it's plugged in.
- CGamesPlay 7y ago
  Doesn’t that mean that a rogue device that did contain software and ignored the incoming packet might actually be trusted by the host device when it shouldn’t be? The twitter thread did say the firmware payload contained no personalization (like encryption keys, perhaps).
  - saagarjha 7y ago
    > The twitter thread did say the firmware payload contained no personalization (like encryption keys, perhaps). To be clear, this just means that the firmware isn't tied to a specific device via the normal ECID/nonce pair like a normal iOS update is.

citrusui 7y ago

For more context, check out this comment on the Panic Blog: https://panic.com/blog/the-lightning-digital-av-adapter-surprise/#comment-16841 https://panic.com/blog/the-lightning-digital-av-adapter-surp...

stefan_ 7y ago
Don't drink the kool-aid. An adapter that destructively compresses the signal is an unexpected and unmitigated disaster, not some cool quirk of Lightning that makes "the host not care what is hanging off it". The real reason this abomination exists is because as recently as 2018, Apple is selling products with a connector that has the equivalent bandwidth of USB 2, not even close to transporting a single 1080p video signal.
- lloeki 7y ago
  It’s destructive, and it probably also introduces a quite decent amount of latency.
- bscphil 7y ago
  Yes - this is really quite astonishing. I imagine any video professional would be horrified to learn that their CABLES were recompressing their video. There's never an acceptable reason for that it's really amazing I haven't heard about it before.
tinus_hn 7y ago
I wonder what they use for the demos at WWDC.