3 ms·

Undocumented for you doesn't remove the possibility that someone, somewhere, has a firm grasp of what that opcode does, and why.

• cat_easdon 7y ago
  Author here - the aim of this project was to explore exactly why such opcodes are problematic for security. Even if they're implemented with entirely innocent intentions - e.g. for debug+verification purposes - they can lead to vulnerabilities in operating systems, emulators, and hypervisors. They induce edge cases which developers can't protect against if they don't know they exist in the first place (due to the lack of any public documentation). There's a more thorough writeup of the project here: https://github.com/cattius/opcodetester/blob/master/thesis.pdf https://github.com/cattius/opcodetester/blob/master/thesis.p....
  • smitty1e 7y ago
    I recall some years ago seeing a post on the OpenBSD mailing list about Intel chip errata and thinking: "I love Big Brother, and Big Brother loves loving me."
  • Craighead 7y ago
    Where's the AMD report?