On Mon, Aug 19, 2013 at 10:26 AM, Matthew Garrett <matthew.garrett@xxxxxxxxxx> wrote: > We have two in-kernel mechanisms for restricting module loading - disabling > it entirely, or limiting it to the loading of modules signed with a trusted > key. These can both be configured in such a way that even root is unable to > relax the restrictions. > > However, right now, there's several other straightforward ways for root to > modify running kernel code. At the most basic level these allow root to > reset the configuration such that modules can be loaded again, rendering > the existing restrictions useless. > > This patchset adds additional restrictions to various kernel entry points > that would otherwise make it straightforward for root to disable enforcement > of module loading restrictions. It also provides a patch that allows the > kernel to be configured such that module signing will be automatically > enabled when the system is booting via UEFI Secure Boot, allowing a stronger > guarantee of kernel integrity. I like this approach of attaching it to the module loading logic. Given the LSM hook for loading modules, I think I'd like to add a hook for the secure_modules() check so that an LSM can respond "secure" as well, if it doing module loading mediation (for example, in the case of Chrome OS's modules-only-from-rootfs). I'll work up a patch... -Kees -- Kees Cook Chrome OS Security -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
