Linked by Thom Holwerda on Wed 3rd Jan 2018 00:42 UTC

A fundamental design flaw in Intel's processor chips has forced a significant redesign of the Linux and Windows kernels to defang the chip-level security bug.

Programmers are scrambling to overhaul the open-source Linux kernel's virtual memory system. Meanwhile, Microsoft is expected to publicly introduce the necessary changes to its Windows operating system in an upcoming Patch Tuesday: these changes were seeded to beta testers running fast-ring Windows Insider builds in November and December.

Crucially, these updates to both Linux and Windows will incur a performance hit on Intel products. The effects are still being benchmarked, however we're looking at a ballpark figure of five to 30 per cent slow down, depending on the task and the processor model. More recent Intel chips have features - such as PCID - to reduce the performance hit.

That's one hell of a bug.

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RE: Affects...
by dnebdal on Wed 3rd Jan 2018 01:25 UTC in reply to "Affects..."
Member since:

From the article, quoting a developer.
"There is presently an embargoed security bug impacting apparently all contemporary [Intel] CPU architectures that implement virtual memory..."

Maybe this is lost in translation but I understood the 286 to introduce Virtual Memory so this presumably affects every Intel CPU made since the 1970s? Yikes

AMD made an LKML post about this, explaining in more detail what sort of bug this is and that they're not vulnerable.

If I understand it correctly (big if), the problem is in the way intel CPUs do speculative execution. Apparently, the speculative branches don't fully respect memory protection, and someone has found a way to turn that into real-world effects. It seems to have been surprising that this was possible.

LKML link:

Edited 2018-01-03 01:29 UTC

Reply Parent Score: 9

RE[2]: Affects...
by BushLin on Wed 3rd Jan 2018 01:30 in reply to "RE: Affects..."
BushLin Member since:

Was just about to edit, yes; so just every Intel x86 from the Pentium Pro onwards, not so bad. ;)

Edited 2018-01-03 01:41 UTC

Reply Parent Score: 7