Re: [PATCH v14 19/19] x86/sgx: Driver documentation

From: Jarkko Sakkinen
Date: Wed Oct 17 2018 - 19:45:42 EST

On Mon, 15 Oct 2018, Pavel Machek wrote:
On Tue 2018-09-25 16:06:56, Jarkko Sakkinen wrote:
+Intel(R) SGX is a set of CPU instructions that can be used by applications to
+set aside private regions of code and data. The code outside the enclave is
+disallowed to access the memory inside the enclave by the CPU access control.
+In a way you can think that SGX provides inverted sandbox. It protects the
+application from a malicious host.

Well, recently hardware had some problems keeping its
promises. So... what about rowhammer, meltdown and spectre?

Doesn't hardware always have this problem over time?

Which ones apply, which ones do not, and on what cpu generations?

Definitely should be refined.

Meltdowns approach AFAIK does not work because reads outside the enclave
will always have a predefined value (-1) but only if the page is present,
which was later exploited in the Foreshadow attack.

Encryption, that sounds nice, but it is hard to do right. If SGX
protected code changes single bit in its memory, how many bits will be
changed in physical RAM?

512-bit blocks and merkle tree based mac. It is pretty well documented
in I'll take not to myself to add
this to the references.

Thanks for the feedback. The ocumentation is hard to drive forward w/o it.