Intel Security Issue Update: Addressing Reboot Issues

Post by dogma1138 » Fri, Jan 12, 2018, 1:16 PM UTC

mtgx wrote: post #89

dogma1138 wrote: post #81

Earlier quoted context omitted.

Meltdown is a Variant of Spectre this isn't how Intel classifies it, this is how Google Project Zero, and heck even Intel's competitor AMD classifies it. https://www.amd.com/en/corporate/speculative-execution https://googleprojectzero.blogspot.co.uk/2018/01/reading-pri... It's also not the scariest variant, it's easily fixed (performance degradation aside), doesn't require a microcode update to be fixed hence is 100%…

Meltdown is not a variant of Spectre. Spectre itself has two variants. And Meltdown was the easiest to exploit. Spectre is "bad" because it affects everyone, but it's less exploitable than Intel's Meltdown.

Post by kmfrk » Fri, Jan 12, 2018, 1:18 PM UTC

rusbus wrote: post #13

I think it's a bit ironic that the text, in a sense, blames Google for these problems by calling them the "Google Project Zero Exploits" as if Google was some sort of cyber crime syndicate using their evil powers to exploit intel.

Post by leeter » Fri, Jan 12, 2018, 1:46 PM UTC

lower wrote: post #52

mrsaint wrote: post #47

Uhm, what a mess. This, just when Linux vendors began pushing updated intel-microcode packages (Ubuntu just released intel-microcode 3.20180108.0). Should we put the update on hold until this issue is hopefully resolved, or should we still update as suggested in the last paragraph of this Intel press release, somehow believing that the random reboots don't apply to "end users"?

Lenovo has put out an advisory about what to do with the BIOS updates that contain the microcode: https://pcsupport.lenovo.com/de/en/product_security/PS500151 Withdrawn CPU Microcode Updates: Intel provides to Lenovo the CPU microcode updates required to address Variant 2, which Lenovo then incorporates into BIOS/UEFI firmware. Intel recently notified Lenovo of quality issues in two of these microcode updates, and co…

Post by throwawaymanbot » Fri, Jan 12, 2018, 1:55 PM UTC

Post by eximius » Fri, Jan 12, 2018, 2:12 PM UTC

EgoIncarnate wrote: post #63

eximius wrote: post #40

Earlier quoted context omitted.

I mean, this one, yea. Speculative execution should not have side effects when wrong because it is Intel silently, sneakily breaking the model of how the CPU works (at least, if you only include the cache in how the PC works and not branch prediction). I would have expected, if I thought to ask, that items were not added to the cache or were removed from the cache if the branch was not retired.

Removing items afterwords probably wouldn't work as you might be able stuff (instead of flush) the cache and figure out which line was emptied. Intel isn't being sneaky, speculative reading was a standard and accepted feature for out of order processors for over 20 years (remember it affects ARM,AMD,Apple,IBM etc as well). Speculative reading privileged memory while unprivileged was a big mistake though.