On Fri, Dec 20, 2013 at 3:11 PM, Eric W. Biederman <ebiederm at xmission.com> wrote: > Vivek Goyal <vgoyal at redhat.com> writes: > >> On Thu, Dec 19, 2013 at 01:54:39PM +0100, Torsten Duwe wrote: >>> On Tue, Nov 26, 2013 at 09:27:59AM -0500, Vivek Goyal wrote: > >>> IMO it's up to user land to search lists of certificates, and present >>> only the final chain of trust to the kernel for checking. >>> >>> ELF is the preferred format for most sane OSes and firmware, and a detached >>> signature would probably be simplest to check. If we have the choice, >>> without restrictions from braindead boot loaders, ELF should be first. >>> And if the pesigning isn't usable and another sig is needed anyway, >>> why not apply that to vmlinux(.gz) ? >> >> I have yet to look deeper into it that if we can sign elf images and >> just use elf loader. And can use space extract the elf image out of >> a bzImage and pass it to kernel. >> >> Even if it is doable, one disadvantage seemed to be that extracted >> elf images will have to be written to a file so thta it's file descriptor >> can be passed to kernel. And that assumed writable root and we chrome >> folks seems to have setups where root is not writable. > > In that case the chrome folks would simply have to use an ELF format > kernel and not a bzImage. If we're doing fd origin verification (not signatures), can't we continue to use a regular bzImage? -Kees -- Kees Cook Chrome OS Security
