如何看待 2018 年 1 月 2 日爆出的 Intel CPU 设计漏洞?

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目前已知的消息(我不完全确定是这样)

  1. 此漏洞会导致低权限应用访问到内核内存
  2. 此漏洞是硬件设计导致的,无法使用microcode修复,只能进行OS级的修复
  3. OS级的修复会导致严重的性能问题,将会导致5%-30%的性能下降
  4. 目前phoronix已对此进行了测试,IO性能几乎下降了50%,编译性能下降了接近30%,postgresql和redis也有差不多20%的性能下跌,详细地址:
Initial Benchmarks Of The Performance Impact Resulting From Linux's x86 Security Changeswww.phoronix.com图标
  1. AMD不受此漏洞影响
Report: Intel CPUs suffer from major security flaw, fix could bring notable performance hit to macOS9to5mac.com图标

-- 英文版的详细信息

Intel: Details und Benchmarks zur Sicherheitslücke in allen CPUswww.computerbase.de图标

-- 最早的新闻来源


@vczh 顺便让轮子哥来作答………………

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2018年1月4日的更新:

根据某发行版Linux的内核组基友的说明,目前推测的性能影响大部分可以取5%的下限,影响最大的是IO频繁的应用环境,所以最大的影响应该是各大公司的数据库服务器。

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继续更新:

这一次由Intel服务器CPU产品诱发的安全事故现在规模正式扩大,确认波及到ARM和AMD,也就是说,近二十年来生产的几乎一切手机、电脑、云计算产品都在风险之列。

安全人员将两个新的漏洞命名为Meltdown(熔断)和Spectre(幽灵),前者允许低权限、用户级别的应用程序“越界”访问系统级的内存,从而造成数据泄露。

听说是由Google Zero团队发现的,目前这个规模就真的很大了……

Spectre affects Intel, AMD, and ARM processors, broadening its reach to include mobile phones, embedded devices, and pretty much anything with a chip in it. Which, of course, is everything from thermostats to baby monitors now.

It works differently from Meltdown; Spectre essentially tricks applications into accidentally disclosing information that would normally be inaccessible, safe inside their protected memory area. This is a trickier one to pull off, but because it’s based on an established practice in multiple chip architectures, it’s going to be even trickier to fix.


主要麻烦的是幽灵这个漏洞………………影响全部CPU………………不单止可以从内核态泄露,虚拟化的也可以………………而且目前没有有效的可行性修复方法………………

参考新闻来源:

Kernel panic! What are Meltdown and Spectre, the bugs affecting nearly every computer and device?techcrunch.com
“Meltdown” and “Spectre”: Every modern processor has unfixable security flawsarstechnica.com图标

有新消息会继续更新。

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from Google Zero:

Testing also showed that an attack running on one virtual machine was able to access the physical memory of the host machine, and through that, gain read-access to the memory of a different virtual machine on the same host.

These vulnerabilities affect many CPUs, including those from AMD, ARM, and Intel, as well as the devices and operating systems running on them.

There is no single fix for all three attack variants; each requires protection independently. Many vendors have patches available for one or more of these attacks.

We will continue our work to mitigate these vulnerabilities and will update both our product support page and this blog post as we release further fixes. More broadly, we appreciate the support and involvement of all the partners and Google engineers who worked tirelessly over the last few months to make our users and customers safe.

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贴一下目前最终的结论

Google Project Zero 和奥地利格拉茨技术大学等机构的研究人员正式披露了三个处理器高危漏洞,分别编号为 CVE-2017-5753(Variant 1)、CVE-2017-5715(Variant 2)和 CVE-2017-5754(Variant 3),前两个漏洞被称为 Spectre,后一个漏洞被称为 Meltdown,Spectre Variant 1 影响 AMD,英特尔和 ARM 处理器,而所有三个漏洞都影响英特尔处理器,研究人员已经开发出了概念验证的漏洞利用。AMDARM 已经发表声明称漏洞可以通过软件修正,对性能影响不大。而英特尔处理器的软件修正则被认为存在显著的性能影响。

目前具体的实例演示是这样的:

总结一下,最后是AMD和ARM都受到Spectre V1影响,就是上边说的全CPU受影响的漏洞,这个漏洞不是硬件级的所以可以比较容易处理,最终AMD和ARM可以通过系统更新来填补漏洞而且不会对性能有重大影响。而Intel目前受到所有三个漏洞影响,最终如何解决不明。

来源:

处理器漏洞 Meltdown 和 Spectrewww.solidot.org