[Ksummit-2012-discuss] [ATTEND] ACPI, UEFI, kernel security

Masami Hiramatsu masami.hiramatsu.pt at hitachi.com
Thu Jun 28 02:28:18 UTC 2012

(2012/06/28 2:37), Steven Rostedt wrote:
> On Wed, 2012-06-27 at 19:28 +0200, Jiri Kosina wrote:
>> On Wed, 27 Jun 2012, Matthew Garrett wrote:
>>> If anything's able to write into kernel memory then I think we've 
>>> already got fairly significant problems. The model I was envisaging 
>>> would involve the kernel verifying the kdump kernel when userspace loads 
>>> it.
>> It's not an exception when kernel security vulnerability gives the 
>> attacker the possibility to overwrite arbitrary memory locations. As UEFI 
>> secure boot is apparently not able to provide any 
>> protection/countermeasure against this, I am really wondering what it is 
>> good for in reality.
> Exactly. As soon as any signed kernel (Windows, Linux or other) has a
> root hole that can modify kernel memory, the entire system has been
> compromised.
> Thus, what is this protecting? Just a bigger wall for crackers to leap
> over?

As far as I know, secure boot is not only for booting but it also
including authentication of all executable binaries include
applications. Thus, the user can't execute any untrusted (not-signed)
binary and programs, as like as viruses, (unauthenticated:))malwares.

However, since it essentially requires that those signed binaries
have NO BUGS and NO VULNERABILITIES against any possible input,
I think it is really hard to achieve that on non-dedicated use.

Thank you,


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