Re: Kdump with signed images

Matthew Garrett
2012-10-26T02:43:11Z

On Thu, Oct 25, 2012 at 09:15:58PM -0400, Mimi Zohar wrote:

> On a running system, the package installer, after verifying the package
> integrity, would install each file with the associated 'security.ima'
> extended attribute. The 'security.evm' digital signature would be
> installed with an HMAC, calculated using a system unique key.

The idea isn't to prevent /sbin/kexec from being modified after
installation - it's to prevent it from being possible to install a
system that has a modified /sbin/kexec. Leaving any part of this up to
the package installer means that it doesn't solve the problem we're
trying to solve here. It must be impossible for the kernel to launch any
/sbin/kexec that hasn't been signed by a trusted key that's been built
into the kernel, and it must be impossible for anything other than
/sbin/kexec to make the kexec system call.

--
Matthew Garrett | mjg59@srcf.ucam.org