Because "timesharing was a mistake" is a hard lesson?
-
-
-
The cynical answer is “because it’s convenient for the Chrome team to think that process separation solves everything”…
- 19 more replies
New conversation -
-
-
Even if the cpu doesn't, in theory the kernel can, and should if necessary. The variants of Spectre that are cross-process are always fixable with heavy machinery by kernel. Only intraprocess ones are unfixable without hardware fixes or pure emulated execution.
-
Why is the kernel able to do it but userspace can’t? There’s no “flush BTB” instruction that I can see, privileged or not…
- 2 more replies
New conversation -
-
-
https://www.phoronix.com/scan.php?page=news_item&px=Spectre-V2-Lite-App-To-App-V3 … and https://lwn.net/Articles/764209/ … are the two most readable explanations I have handy.
-
OK, I see there’s a new instruction for indirect branches (but not direct ones?) Anyway, what stops us from making threads (as opposed to processes) that are separated with IBPB?
- 1 more reply
New conversation -
-
-
This is more complicated than a single tweet can express. Intel has a good short document laying out its branch predictors and available hardware and software mitigations here: https://software.intel.com/security-software-guidance/api-app/sites/default/files/336996-Speculative-Execution-Side-Channel-Mitigations.pdf …
-
The ultimate solution is to do everything that document says and turn off hyperthreading.
End of conversation
New conversation -
-
-
Process isolation helps defend against the v1 array-bounds-checks attacks, by the rather brute-force defence of separate address spaces. You can imagine similar defences in user-land, but you'd need a security check that's guaranteed not to be speculated past.
Thanks. Twitter will use this to make your timeline better. UndoUndo
-
-
-
What's the attack here? Process A determining which branches process B has taken?
-
Google lays out the scenario here in the variant 2 section: https://googleprojectzero.blogspot.com/2018/01/reading-privileged-memory-with-side.html?m=1 …
- 3 more replies
New conversation -
Loading seems to be taking a while.
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.