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Overview of Intel SGX – Part 1, SGX Internals

70 points by gbrown_ 8y ago

dman 8y ago
Nice diagrams - any pointers on what tool was used to make these?
- tyingq 8y ago
  Maybe this? https://mathematica.stackexchange.com/questions/11350/xkcd-style-plots https://mathematica.stackexchange.com/questions/11350/xkcd-s...
  - gh02t 8y ago
    Making those diagrams in Mathematica would be extraordinary painful. It's probably something similar to that (a custom XKCD-like style) but for a dedicated diagramming tool. I don't know of any tool with such a style though, so I'm guessing it's custom.
  - deleted 8y ago
    [deleted]
- okl 8y ago
  Looks like Visio with the "handdrawn" design/theme.
gyrfalcon 8y ago
"It allows user-land code to create private memory regions, called enclaves, that are isolated from other processes running at the same or higher privilege levels" ... Except when it doesn't https://www.schneier.com/blog/archives/2017/03/using_intels_sg.html https://www.schneier.com/blog/archives/2017/03/using_intels_... More junk in the processor like the Intel management engine.
deleted 8y ago
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mehrdadn 8y ago
Anybody know why SGX installs additional service(s) in the system, and how they are used/what they are needed for? There is "Intel SGX AESM" with the description "The system services management agent for Intel(R) Software Guard Extensions enabled applications", but I don't get what exactly it manages and how it can be used to manage that. Where/how does it come into play?
- thinkmoore 8y ago
  Various components of the SGX system (launch approval, remote attestation quote signing, etc) are implemented as Intel provided enclaves. AESM manages those enclaves and provides an untrusted API to communicate with them.
  - mehrdadn 8y ago
    Interesting, thanks!
Taniwha 8y ago
what we all know now about extracting information from cache miss and TLB timings sort of makes all this a bit moot now doesn't it
- gcb0 8y ago
  To be honest I clicked hopping to read about a SGX exploit enabling more of those.
- staticassertion 8y ago
  The attacker's assumed capability is arbitrary execution locally. Assuming an attacker is running as a separate user from the secret they want to steal (reasonable assumption, in my opinion) they need a vulnerability in the kernel, or some service running as root. Probably the kernel. SGX pushes that further - you need a vulnerability in the hardware. The attack surface of your hardware is < the attack surface of your hardware + kernel, so it seems like a win. We'll continue to see attacks against hardware, but this is still a technology worth exploring.
deleted 8y ago
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70 points by gbrown_ 8y ago

dman 8y ago

Nice diagrams - any pointers on what tool was used to make these?

tyingq 8y ago
Maybe this? https://mathematica.stackexchange.com/questions/11350/xkcd-style-plots https://mathematica.stackexchange.com/questions/11350/xkcd-s...
- gh02t 8y ago
  Making those diagrams in Mathematica would be extraordinary painful. It's probably something similar to that (a custom XKCD-like style) but for a dedicated diagramming tool. I don't know of any tool with such a style though, so I'm guessing it's custom.
- deleted 8y ago
  [deleted]
okl 8y ago
Looks like Visio with the "handdrawn" design/theme.

gyrfalcon 8y ago

"It allows user-land code to create private memory regions, called enclaves, that are isolated from other processes running at the same or higher privilege levels" ... Except when it doesn't https://www.schneier.com/blog/archives/2017/03/using_intels_sg.html https://www.schneier.com/blog/archives/2017/03/using_intels_... More junk in the processor like the Intel management engine.

deleted 8y ago

[deleted]

mehrdadn 8y ago

Anybody know why SGX installs additional service(s) in the system, and how they are used/what they are needed for? There is "Intel SGX AESM" with the description "The system services management agent for Intel(R) Software Guard Extensions enabled applications", but I don't get what exactly it manages and how it can be used to manage that. Where/how does it come into play?

thinkmoore 8y ago
Various components of the SGX system (launch approval, remote attestation quote signing, etc) are implemented as Intel provided enclaves. AESM manages those enclaves and provides an untrusted API to communicate with them.
- mehrdadn 8y ago
  Interesting, thanks!

Taniwha 8y ago

what we all know now about extracting information from cache miss and TLB timings sort of makes all this a bit moot now doesn't it

gcb0 8y ago
To be honest I clicked hopping to read about a SGX exploit enabling more of those.
staticassertion 8y ago
The attacker's assumed capability is arbitrary execution locally. Assuming an attacker is running as a separate user from the secret they want to steal (reasonable assumption, in my opinion) they need a vulnerability in the kernel, or some service running as root. Probably the kernel. SGX pushes that further - you need a vulnerability in the hardware. The attack surface of your hardware is < the attack surface of your hardware + kernel, so it seems like a win. We'll continue to see attacks against hardware, but this is still a technology worth exploring.

deleted 8y ago

[deleted]