brandonb927

#!/bin/sh

###
# SOME COMMANDS WILL NOT WORK ON macOS (Sierra or newer)
# For Sierra or newer, see https://github.com/mathiasbynens/dotfiles/blob/master/.macos
###

# Alot of these configs have been taken from the various places
# on the web, most from here
# https://github.com/mathiasbynens/dotfiles/blob/5b3c8418ed42d93af2e647dc9d122f25cc034871/.osx

XVilka

THIS GIST WAS MOVED TO TERMSTANDARD/COLORS REPOSITORY.

PLEASE ASK YOUR QUESTIONS OR ADD ANY SUGGESTIONS AS A REPOSITORY ISSUES OR PULL REQUESTS INSTEAD!

PurpleBooth

Project Title

One Paragraph of project description goes here

Getting Started

These instructions will get you a copy of the project up and running on your local machine for development and testing purposes. See deployment for notes on how to deploy the project on a live system.

Prerequisites

headius

Algorithm

1. A secret byte you want to read is stored at inaccessible memory location priv_mem.
2. The sender triggers an access exception by attempting to read priv_mem.
3. Due to CPU optimization (out-of-order execution), the load of secret from priv_mem and the use of its value in (4) and (5) below may execute before the exception is triggered.
4. Calculate an offset into a known array probe by multiplying secret by the width of a cache line (or whatever block size the CPU typically fetches, like a 4096-byte page). This guarantees each of those 256 possible offsets will cache separately.
5. Load probe[offset], which causes the CPU to cache exactly one chunk of of our array, populating one cache line.
6. The exception finally triggers, clearing the modified registers...but cached data is not excised.
7. Iterate over all 256 offsets into probe to find out which one loads fast. You've determined the value of secret.