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Intel junk...Kernel-memory-leaking Intel processor design flaw forcesLinux, Windows redesign
Performance hits loom, other OSes need fixes
Updated 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. Your mileage may vary. The Register ? @TheRegister PostgreSQL SELECT 1 with the KPTI workaround for Intel CPU vulnerability https://www.postgresql.org/message- Best case: 17% slowdown Worst case: 23% 3:58 PM - Jan 2, 2018 12 12 Replies 331 331 Retweets 212 212 likes Twitter Ads info and privacy Similar operating systems, such as Apple's 64-bit macOS, will also need to be updated the flaw is in the Intel x86-64 hardware, and it appears a microcode update can't address it. It has to be fixed in software at the OS level, or go 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. However, some details of the flaw have surfaced, and so this is what we know. Impact It is understood the bug is present in modern Intel processors produced in the past decade. It allows normal user programs from database applications to JavaScript in web browsers to discern to some extent the layout or contents of protected kernel memory areas. The fix is to separate the kernel's memory completely from user processes using what's called Kernel Page Table Isolation, or KPTI. At one point, Forcefully Unmap Complete Kernel With Interrupt Trampolines, aka ****WIT, was mulled by the Linux kernel team, giving you an idea of how annoying this has been for the developers. Whenever a running program needs to do anything useful such as write to a file or open a network connection it has to temporarily hand control of the processor to the kernel to carry out the job. To make the transition from user mode to kernel mode and back to user mode as fast and efficient as possible, the kernel is present in all processes' virtual memory address spaces, although it is invisible to these programs. When the kernel is needed, the program makes a system call, the processor switches to kernel mode and enters the kernel. When it is done, the CPU is told to switch back to user mode, and reenter the process. While in user mode, the kernel's code and data remains out of sight but present in the process's page tables. Think of the kernel as God sitting on a cloud, looking down on Earth. It's there, and no normal being can see it, yet they can pray to it. These KPTI patches move the kernel into a completely separate address space, so it's not just invisible to a running process, it's not even there at all. Really, this shouldn't be needed, but clearly there is a flaw in Intel's silicon that allows kernel access protections to be bypassed in some way. The downside to this separation is that it is relatively expensive, time wise, to keep switching between two separate address spaces for every system call and for every interrupt from the hardware. These context switches do not happen instantly, and they force the processor to dump cached data and reload information from memory. This increases the kernel's overhead, and slows down the computer. Your Intel-powered machine will run slower as a result. How can this security hole be abused? At best, the vulnerability could be leveraged by malware and hackers to more easily exploit other security bugs. At worst, the hole could be abused by programs and logged-in users to read the contents of the kernel's memory. Suffice to say, this is not great. The kernel's memory space is hidden from user processes and programs because it may contain all sorts of secrets, such as passwords, login keys, files cached from disk, and so on. Imagine a piece of JavaScript running in a browser, or malicious software running on a shared public cloud server, able to sniff sensitive kernel-protected data. Specifically, in terms of the best-case scenario, it is possible the bug could be abused to defeat KASLR: kernel address space layout randomization. This is a defense mechanism used by various operating systems to place components of the kernel in randomized locations in virtual memory. This mechanism can thwart attempts to abuse other bugs within the kernel: typically, exploit code particularly return-oriented programming exploits relies on reusing computer instructions in known locations in memory. If you randomize the placing of the kernel's code in memory, exploits can't find the internal gadgets they need to fully compromise a system. The processor flaw could be potentially exploited to figure out where in memory the kernel has positioned its data and code, hence the flurry of software patching. However, it may be that the vulnerability in Intel's chips is worse than the above mitigation bypass. In an email to the Linux kernel mailing list over Christmas, AMD said it is not affected. The wording of that message, though, rather gives the game away as to what the underlying cockup is: AMD processors are not subject to the types of attacks that the kernel page table isolation feature protects against. The AMD microarchitecture does not allow memory references, including speculative references, that access higher privileged data when running in a lesser privileged mode when that access would result in a page fault. A key word here is "speculative." Modern processors, like Intel's, perform speculative execution. In order to keep their internal pipelines primed with instructions to obey, the CPU cores try their best to guess what code is going to be run next, fetch it, and execute it. It appears, from what AMD software engineer Tom Lendacky was suggesting above, that Intel's CPUs speculatively execute code potentially without performing security checks. It seems it may be possible to craft software in such a way that the processor starts executing an instruction that would normally be blocked such as reading kernel memory from user mode and completes that instruction before the privilege level check occurs. That would allow ring-3-level user code to read ring-0-level kernel data. And that is not good. The specifics of the vulnerability have yet to be confirmed, but consider this: the changes to Linux and Windows are significant and are being pushed out at high speed. That suggests it's more serious than a KASLR bypass. Also, the updates to separate kernel and user address spaces on Linux are based on a set of fixes dubbed the KAISER patches, which were created by eggheads at Graz University of Technology in Austria. These boffins discovered [PDF] it was possible to defeat KASLR by extracting memory layout information from the kernel in a side-channel attack on the CPU's virtual memory system. The team proposed splitting kernel and user spaces to prevent this information leak, and their research sparked this round of patching. Their work was reviewed by Anders Fogh, who wrote this interesting blog post in July. That article described his attempts to read kernel memory from user mode by abusing speculative execution. Although Fogh was unable to come up with any working proof-of-concept code, he noted: My results demonstrate that speculative execution does indeed continue despite violations of the isolation between kernel mode and user mode. It appears the KAISER work is related to Fogh's research, and as well as developing a practical means to break KASLR by abusing virtual memory layouts, the team may have somehow proved Fogh right that speculative execution on Intel x86 chips can be exploited to access kernel memory. Shared systems The bug will impact big-name cloud computing environments including Amazon EC2, Microsoft Azure, and Google Compute Engine, said a software developer blogging as Python Sweetness in this heavily shared and tweeted article on Monday: There is presently an embargoed security bug impacting apparently all contemporary [Intel] CPU architectures that implement virtual memory, requiring hardware changes to fully resolve. Urgent development of a software mitigation is being done in the open and recently landed in the Linux kernel, and a similar mitigation began appearing in NT kernels in November. In the worst case the software fix causes huge slowdowns in typical workloads. There are hints the attack impacts common virtualisation environments including Amazon EC2 and Google Compute Engine... Microsoft's Azure cloud which runs a lot of Linux as well as Windows will undergo maintenance and reboots on January 10, presumably to roll out the above fixes. Amazon Web Services also warned customers via email to expect a major security update to land on Friday this week, without going into details. There were rumors of a severe hypervisor bug possibly in Xen doing the rounds at the end of 2017. It may be that this hardware flaw is that rumored bug: that hypervisors can be attacked via this kernel memory access cockup, and thus need to be patched, forcing a mass restart of guest virtual machines. A spokesperson for Intel was not available for comment. Ž Updated to add The Intel processor flaw is real. A PhD student at the systems and network security group at Vrije Universiteit Amsterdam has developed a proof-of-concept program that exploits the Chipzilla flaw to read kernel memory from user mode: View image on Twitter View image on Twitter brainsmoke @brainsmoke Bingo! #kpti #intelbug 6:28 AM - Jan 3, 2018 58 58 Replies 1,687 1,687 Retweets 2,362 2,362 likes Twitter Ads info and privacy The Register has also seen proof-of-concept exploit code that leaks a tiny amount of kernel memory to user processes. Finally, macOS has been patched to counter the chip design blunder since version 10.13.2, according to operating system kernel expert Alex Ionescu. And it appears 64-bit ARM Linux kernels will also get a set of KAISER patches, completely splitting the kernel and user spaces, to block attempts to defeat KASLR. We'll be following up this week. https://www.theregister.co.uk/2018/0...u_design_flaw/ -- Windows 2000 Pro RC2 on Alpha. |
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Intel junk...Kernel-memory-leaking Intel processor design flaw forces Linux, Windows redesign
Designed By India H1B Engineers wrote:
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. This is ugly. Think of the large computing centers, for example Google's data centers. Suddenly, they will need significantly more CPU time, and thus electricity (and thus carbon), to get the job done? -- "Half say its easier than Windows and the other (more truthful) half maintain that they are GLAD Linux is buggy and error prone because it puts off the great unwashed that would otherwise pollute the Linux gene pool." - "True Linux advocate" Hadron Quark |
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Intel junk...Kernel-memory-leaking Intel processor design flawforces Linux, Windows redesign
On 4/1/2018 23:28, chrisv wrote:
This is ugly. Think of the large computing centers, for example Google's data centers. Suddenly, they will need significantly more CPU time, and thus electricity (and thus carbon), to get the job done? That only made all electricity companies happy... -- @~@ Remain silent! Drink, Blink, Stretch! Live long and prosper!! / v \ Simplicity is Beauty! /( _ )\ May the Force and farces be with you! ^ ^ (x86_64 Ubuntu 9.10) Linux 2.6.39.3 ä¸ĺ貸! ä¸čŠé¨! ä¸ć´äş¤! ä¸ć交! ä¸ćĺŤ! ä¸čŞćŽş! čŤčć Žçść´ (CSSA): http://www.swd.gov.hk/tc/index/site_...sub_addressesa |
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Intel junk...Kernel-memory-leaking Intel processor design flawforces Linux, Windows redesign
On 2018-01-04, chrisv wrote:
This is ugly. Think of the large computing centers, for example Google's data centers. Suddenly, they will need significantly more CPU time, and thus electricity (and thus carbon), to get the job done? Carbon is not a pollutant, except in the "minds" of left-wing loons, so that is not of any importance. (I certainly refuse to lower my carbon output. Environmentalist scum who desire to lower theirs are welcome to stop breathing. However, I digress.) The loss of performance could significantly increase the cost of operations for large computing centers. Look for the cost of online services to rise. -- ----------------------------------------------------------------------------- Roger Blake (Posts from Google Groups killfiled due to excess spam.) NSA sedition and treason -- http://www.DeathToNSAthugs.com Don't talk to cops! -- http://www.DontTalkToCops.com Badges don't grant extra rights -- http://www.CopBlock.org ----------------------------------------------------------------------------- |
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Intel junk...Kernel-memory-leaking Intel processor design flaw forces Linux, Windows redesign
On Thu, 4 Jan 2018 17:44:04 -0000 (UTC), Roger Blake
wrote: On 2018-01-04, chrisv wrote: This is ugly. Think of the large computing centers, for example Google's data centers. Suddenly, they will need significantly more CPU time, and thus electricity (and thus carbon), to get the job done? Carbon is not a pollutant, except in the "minds" of left-wing loons, so that is not of any importance. (I certainly refuse to lower my carbon output. Environmentalist scum who desire to lower theirs are welcome to stop breathing. However, I digress.) The loss of performance could significantly increase the cost of operations for large computing centers. Look for the cost of online services to rise. Might I say that was an awesome post, sir. |
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Intel junk...Kernel-memory-leaking Intel processor design flawforces Linux, Windows redesign
Den 2018-01-04 kl. 18:44, skrev Roger Blake:
On 2018-01-04, chrisv wrote: This is ugly. Think of the large computing centers, for example Google's data centers. Suddenly, they will need significantly more CPU time, and thus electricity (and thus carbon), to get the job done? Carbon is not a pollutant, except in the "minds" of left-wing loons, so that is not of any importance. (I certainly refuse to lower my carbon output. Environmentalist scum who desire to lower theirs are welcome to stop breathing. However, I digress.) The carbon you breath comes from the food you eat. No problem. But much of the carbon that we let out comes from carbon from millions years ago (fosile fuels). *That* is a major problem. Burning bilological fuels (that grow the last 100 years) is not any problem either. You other statements are purelly childish and uneducated. The loss of performance could significantly increase the cost of operations for large computing centers. Look for the cost of online services to rise. |
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Intel junk...Kernel-memory-leaking Intel processor design flawforces Linux, Windows redesign
On Thu,4 Jan 2018 13:56:45 wrote:
has to be fixed in software at the OS level, or go buy a new processor without the design blunder. not a blunder it is deliberate |
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Intel junk...Kernel-memory-leaking Intel processor design flaw forces Linux, Windows redesign
Jan-Erik Soderholm wrote:
Den 2018-01-04 kl. 18:44, skrev Roger Blake: Carbon is not a pollutant, except in the "minds" of left-wing loons, so that is not of any importance. (I certainly refuse to lower my carbon output. Environmentalist scum who desire to lower theirs are welcome to stop breathing. However, I digress.) The carbon you breath comes from the food you eat. No problem. But much of the carbon that we let out comes from carbon from millions years ago (fosile fuels). *That* is a major problem. Burning bilological fuels (that grow the last 100 years) is not any problem either. You other statements are purelly childish and uneducated. Might I say that was an awesome post, sir. -- "If only 2% of the world believes that GNU/Linux is great, then THEY are the liars for claiming that it's a quality piece of software." - "Slimer", AKA "Doomsdrzej" |
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Intel junk...Kernel-memory-leaking Intel processor design flawforces Linux, Windows redesign
chrisv wrote:
Designed By India H1B Engineers wrote: 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. This is ugly. Think of the large computing centers, for example Google's data centers. Suddenly, they will need significantly more CPU time, and thus electricity (and thus carbon), to get the job done? And once all the spanners are tossed into the works, which will slow things down, what happens when new CPUs without the issues are available? Will computers forever be artificially slowed down? A whole bunch of someones has seriously dropped the ball on this. Protected memory should be just that, protected, with no way to avoid the protection. -- David Froble Tel: 724-529-0450 Dave Froble Enterprises, Inc. E-Mail: DFE Ultralights, Inc. 170 Grimplin Road Vanderbilt, PA 15486 |
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Intel junk...Kernel-memory-leaking Intel processor design flaw forces Linux, Windows redesign
"Roger Blake" wrote in message
... On 2018-01-04, chrisv wrote: This is ugly. Think of the large computing centers, for example Google's data centers. Suddenly, they will need significantly more CPU time, and thus electricity (and thus carbon), to get the job done? Carbon is not a pollutant, except in the "minds" of left-wing loons, so that is not of any importance. (I certainly refuse to lower my carbon output. Environmentalist scum who desire to lower theirs are welcome to stop breathing. However, I digress.) The loss of performance could significantly increase the cost of operations for large computing centers. Look for the cost of online services to rise. Rise? After the deal Trump gave them? Billions more in profit from saved taxes. Those Big Corp execs can really vacation now!! -- Buffalo |
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Intel junk...Kernel-memory-leaking Intel processor design flawforces Linux, Windows redesign
On 1/4/2018 10:29 AM, chrisv wrote:
Jan-Erik Soderholm wrote: Den 2018-01-04 kl. 18:44, skrev Roger Blake: Carbon is not a pollutant, except in the "minds" of left-wing loons, so that is not of any importance. (I certainly refuse to lower my carbon output. Environmentalist scum who desire to lower theirs are welcome to stop breathing. However, I digress.) The carbon you breath comes from the food you eat. No problem. But much of the carbon that we let out comes from carbon from millions years ago (fosile fuels). *That* is a major problem. Burning bilological fuels (that grow the last 100 years) is not any problem either. You other statements are purelly childish and uneducated. Might I say that was an awesome post, sir. Agreed! |
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Intel junk...Kernel-memory-leaking Intel processor design flawforces Linux, Windows redesign
Den 2018-01-04 kl. 23:04, skrev Tim Streater:
In article , DaveFroble wrote: chrisv wrote: Designed By India H1B Engineers wrote: 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. This is ugly.Â* Think of the large computing centers, for example Google's data centers.Â* Suddenly, they will need significantly more CPU time, and thus electricity (and thus carbon), to get the job done? And once all the spanners are tossed into the works, which will slow things down, what happens when new CPUs without the issues are available?Â* Will computers forever be artificially slowed down? A whole bunch of someones has seriously dropped the ball on this. Protected memory should be just that, protected, with no way to avoid the protection. But AIUI, the protection isn't applied when the CPU does speculative instruction execution. It's unclear why, though. Becuse the designers, for performance reasons, has mapped kernel memory into the user process address space and relies on the OS to check protection before any kernel memory (or code) is accessed. The issue with the current issues is that the hardware (the CPU) does these accesses in hardware "under the hood" without control by the OS. If you map your kernel memory in another way that uses the hardware protection facilities, you are (as I understand) safe, at the cost of worse performance to switch between user and kernel mode. |
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Intel junk...Kernel-memory-leaking Intel processor design flaw forces Linux, Windows redesign
On 2018-01-04 15:28:17 +0000, chrisv said:
Designed By India H1B Engineers wrote: 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. This is ugly. Think of the large computing centers, for example Google's data centers. Suddenly, they will need significantly more CPU time, and thus electricity (and thus carbon), to get the job done? It aint just Intel either. The three different CPU issues affect chips from Intel, AMD, and ARM (no mention anywhere of PowerPC or Apple's own A-series), and affect virtually all devices sold in the last 15 years - computers, tablets, smartphones, etc.! That's gonna be one heck of a clean up bill! :-( Apple has already partially fixed the problems in the MacOS X High Sierra update 10.13.2 (with no noticeable performance slow-down) and further fixes due in the up-coming 10.13.3 update currently in beta testing. Users of old versions of OS X may well be stuck though and not get any update. |
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Intel junk...Kernel-memory-leaking Intel processor design flawforces Linux, Windows redesign
On 2018-01-04, chrisv wrote:
Might I say that was an awesome post, sir. His post was sheer idiocy. CO2 is not a pollutant - period. Human caused "climate change/global warming" is junk science at its worst. Even Reid Bryson, the scientist who was the father of modern climate science, stated that it is "a bunch of hooey." As I said, I absolutely refuse to reduce my own carbon emissions and in fact continue to see ways to increase them. (Do you dumbass hippies really believe that your stoopid windmills are solar panels are capable of keeping people warm and alive in the deep freeze that so much of the U.S. is currently experiencing?) -- ----------------------------------------------------------------------------- Roger Blake (Posts from Google Groups killfiled due to excess spam.) NSA sedition and treason -- http://www.DeathToNSAthugs.com Don't talk to cops! -- http://www.DontTalkToCops.com Badges don't grant extra rights -- http://www.CopBlock.org ----------------------------------------------------------------------------- |
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Intel junk...Kernel-memory-leaking Intel processor design flawforces Linux, Windows redesign
On 05/01/2018 03:36, Roger Blake wrote:
Do you dumbass hippies really believe that your stoopid windmills are solar panels are capable of keeping people warm and alive in the deep freeze that so much of the U.S. is currently experiencing?) Why can't you cuddle up to keep warm like your cousins in this picture? https://s-media-cache-ak0.pinimg.com...d3fb4b2de4.jpg https://s-media-cache-ak0.pinimg.com/originals/98/b1/6b/98b16bdb3a0907553e86a1d3fb4b2de4.jpg -- With over 600 million devices now running Windows 10, customer satisfaction is higher than any previous version of windows. |
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