'Kernel Memory Leaking' Intel Processor Design Flaw Forces Linux, Windows Redesign (theregister.co.uk)

According to The Register, "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." From the report: 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 this month's 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 -- specifically, PCID -- to reduce the performance hit. Similar operating systems, such as Apple's 64-bit macOS, will also need to be updated -- the flaw is in the Intel x86 hardware, and it appears a microcode update can't address it. It has to be fixed in software at the OS level, or buy a new processor without the design blunder. Details of the vulnerability within Intel's silicon are under wraps: an embargo on the specifics is due to lift early this month, perhaps in time for Microsoft's Patch Tuesday next week. Indeed, patches for the Linux kernel are available for all to see but comments in the source code have been redacted to obfuscate the issue. The report goes on to share some details of the flaw that have surfaced. "It is understood the bug is present in modern Intel processors produced in the past decade," reports The Register. "It allows normal user programs -- from database applications to JavaScript in web browsers -- to discern to some extent the contents of protected kernel memory. The fix is to separate the kernel's memory completely from user processes using what's called Kernel Page Table Isolation, or KPTI."

Comments

Re:five to 30 per cent slow down

[epine]

I find it hard to believe that a virtual memory change will result in a 5-30% slowdown for Intel processors. Maybe for a few extremely specific (likely edge-case) tasks, but if there was a legitimate 5-30% performance decrease, you can bet there would be a far different solution in the works that would suitably fix the problem.

Of course, if microcode update fails, there's always the hail Mary unicorn ass-pull.

I assure you, every Intel employee is kneeling on the carpet this very instant, facing the most auspicious astrological direction like ten of thousands of well-aligned human magnetic domains, while praying in unison like a telepathic Tourettic cuckoo clocks to any qualified god who will take their call.

If you've been harbouring a time machine, looking for optimal market conditions, I suggest you pull it out of your ... hiding place ... any minute now, because the market is ripe, ripe, ripe and bidding will begin with a B.

What a fucking nightmare.